Editor's note: CNN's Nima Elbagir, Lillian Leposo and Nick Migwe made the dangerous journey to Chibok, Nigeria, to gather firsthand accounts of the abduction of the schoolgirls -- and how people in the northeastern town are still living in fear.
Chibok, Nigeria (CNN) -- The terrifying news began to spread before the gun-wielding Islamist militants made it into Chibok last month. Villagers began to receive cell phone calls that the feared extremist group Boko Haram was on the way.
No one knew what the attack would entail, that it would mean hundreds of schoolgirls plucked from their beds by a group of extremists who would later threaten to sell them.
"It's like they were coming for a shopping trip," a villager who witnessed the attack told CNN.
Some lucky girls managed to escape that night when, after they were loaded into cargo trucks, they made a dash for freedom.
"We would rather die than go," one of the girls told CNN. "We ran into the bush. We ran and we ran."
With fear in her eyes and voice, the young woman, who asked not to be identified, described the experience to a CNN crew that made the long, dangerous trip to her village.
She said she and two friends who had also escaped saw something on fire and headed in that direction, presuming it was building in the village that had been set ablaze. Normally, Chibok is pitch black at night.
Officials have said that Boko Haram militants abducted 276 girls from the boarding school on April 14 and that some escaped into a forest.
Villagers said they passed along warnings to local police that the terrorists were on their way that night. They said they received phone calls from family and friends from surrounding villages and were told that there was a convoy of cargo trucks, pickups and motorcycles heading their way.
One villager said he was told, "They are coming for you. Run!"
The villagers said police called for reinforcements, but none came. Everyone, including the police, fled into the bush during the attack. But the girls were asleep in their dorms.
The stories appear to confirm an Amnesty International report that the government couldn't put together enough troops to head off the attack.
The girl who described her escape to CNN was still shaken up by the events. When asked to describe what her kidnappers wore, she responded: "I feel afraid."
Her school is closed, but if it were open, she says, she wouldn't go back.
There are many checkpoints on the roads from the capital of Abuja to Chibok. Some of these are manned by the military. Others have local vigilantes, armed with machetes, posted there.
The stops are too many to count and have turned what should be an eight- to 10-hour trip into a journey that took CNN's crew four days.
At each checkpoint, someone will ask where you are headed, poke his head in the vehicle and look around. Sometimes, he will ask to check passports.
The absence of a security stop is noticeable when cars turn off the main, paved road onto the clay-topped, pothole-filled path to Chibok. There are no checkpoints for the last hour.
The village is home to hundreds of people, and despite the abduction, life appears to be almost normal. Children play in the streets; men and women go to work.
The primary place of business in town, the open-air market, is busy even after nightfall, though not for long. At the stands, villagers try to charge their mobile phones through power strips attached to gasoline-powered generators. Rarely does electricity flow through the grid. Solar-powered streetlights never work.
When the women, children and elderly go to sleep, the young men station themselves throughout the village. Every group has its own area of operation where the men -- who work during the day and must get very little sleep -- do security patrols throughout the night. Each of them carries a machete, a poisoned bow and arrow or, in some cases, a homemade gun.
Many in the village said they hope this will help put pressure on the government to do more to find their girls.
Nigerian President Goodluck Jonathan said Saturday that he was worried about the girls and thanked other countries, including the United States, that have pledged support in finding them.
"We promise the world that we must get these girls out," Jonathan said.
CIA Director John Brennan told the TV network Fusion that the United States is doing "everything we can" to determine the girls' location, a mission President Barack Obama has made a priority.
U.S. and British officials are in Abuja to help Nigeria's government look for the girls, plan rescue missions and advise on ways to subdue Boko Haram. China and France are also helping in the search. A statement from Jonathan's office Sunday said Israeli Prime Minister Benjamin Netanyahu promised to send a team of counterterrorism experts.
Several senior officials at the U.S. State Department told CNN that Washington offered assistance in the immediate aftermath of the mass abduction, echoing comments last week by Secretary of State John Kerry that the U.S. has been engaged since Day 1. Nigeria turned down the offer until it became apparent that the situation needed a greater response.
Nigeria denies receiving warning
Scrutiny of the Nigerian government's response to the kidnappings escalated after a report Friday from Amnesty International that says authorities knew at least four hours before the attack that Boko Haram was on its way.
The Amnesty International report alleges that Nigerian commanders were unable to raise enough troops to respond.
A military contingent of between 15 and 17 soldiers and a handful of police officers in Chibok were unable to fend off as many as 200 Boko Haram fighters who stole the girls from their beds, the report says.
The Nigerian government said it responded with troops, helicopters and airplanes in the immediate aftermath of the mass abduction.
Amnesty International Secretary General Salil Shetty wrote an opinion piece for Sunday's editions of the Independent newspaper of Britain that said the organization stands by its claims.
Many have died in violence
Nigerian officials have frequently been criticized for failing to prevent Boko Haram's deadly attacks, particularly in the terror group's stronghold of northeastern Nigeria.
At least 2,000 people have died in violence in northern Nigeria this year, Amnesty said. The most recent Boko Haram attack killed at least 310 people in a town that had been used as a staging ground for troops searching for the missing girls.
The International Criminal Court said the number and intensity of attacks has risen sharply this year.
It called on Boko Haram to release the girls immediately.
"The troubling phenomenon of targeting females during conflict, this time, in Borno state, cannot be tolerated and must be stopped," said prosecutor Fatou Bensouda. "No stone should be left unturned to bring those responsible for such atrocious acts to justice, either in Nigeria or at the ICC."
Disagreement on where girls might be
The girls who remain missing probably have been separated and taken out of the country, some officials have said.
"I abducted your girls," Boko Haram leader Abubakar Shekau said in a video released last week. "There is a market for selling humans. Allah says I should sell. He commands me to sell."
U.S. Navy Rear Adm. John Kirby, who serves as Pentagon press secretary, said officials believe that the girls "have been broken up into smaller groups" but declined to detail how they came to the conclusion. His sentiment has been echoed by others.
"The search must be in Niger, Cameroon and Chad, to see if we can find information," said Gordon Brown, a former UK prime minister and the U.N.'s special envoy for global education.
But Jonathan believes the girls are still in Nigeria, somewhere in the Sambisa forest.
"If they move that number of girls into Cameroon, people will see. So I believe they are still in Nigeria," he said.
Prime Minister David Cameron promised Sunday that Britain "will do what we can" to help find the girls.
He made the comments as he held a sign bearing the #BringBackOurGirls hashtag on the BBC's "Andrew Marr Show."
Cameron and Pope Francis are the latest high-profile supporters of the social media campaign. U.S. first lady Michelle Obama tweeted a photo of herself with a similar poster last week.
The Pope tweeted Saturday: "Let us all join in prayer for the immediate release of the schoolgirls kidnapped in Nigeria. #BringBackOurGirls."
Also Saturday, Michelle Obama condemned the "unconscionable" kidnapping of the girls, saying in the weekly White House address that it was the work of "a terrorist group determined to keep these girls from getting an education.
CNN's Vladimir Duthiers, Isha Sesay, Nana Karikari-apau, Elise Labott, Lindsay Isaac and Chelsea J. Carter contributed to this report.