Geneva, Switzerland (CNN) -- It's a brief reprieve for hundreds of Syrian civilians trapped for months in a besieged city.
The Syrian government and opposition have agreed to extend a truce in Homs by another three days, the United Nations said.
"I hope this will allow us to evacuate yet more civilians and deliver much needed additional supplies," said Valerie Amos, the U.N. humanitarian chief. "The protection of civilians caught up in this horrendous conflict in Syria is the greatest priority for U.N. agencies and humanitarian partners."
More than 800 civilians have been given safe passage out of the city since the deal was put in place Friday, she said in a statement.
Syria's Red Crescent tweeted that a group of around 300 people were taken to safety early Monday.
Parts of Homs have been under siege since June 2012.
Under fire in Homs
The U.N.-brokered truce has been violated several times.
Vehicles from the Red Crescent and United Nations had a difficult time entering the city over the weekend as they were targeted by gunfire and explosives.
Eleven people were killed as the operations were being carried out, said Amos.
"People seeking refuge and those carrying out humanitarian operations should not be fired on," Amos said in a statement
"U.N. and Red Crescent workers told me that many of the people who left Old Homs were traumatized and weak. They also said that they witnessed terrible conditions at the field hospital in the Old City, where the equipment is basic, there are no medicines and people are in urgent need of medical attention."
Social media video from inside Homs captured some of the chaotic scenes as desperate people lined up for a chance to leave.
One clip shows dozens of residents sitting or standing around several U.N. vans. An activist behind camera comments that are not enough vehicles for all the waiting families, while a U.N. worker yells: "We need to move and we will come back."
Another part of the same video shows a woman looking desperately for her lost son. "How can I leave without him? He is my son," she says and screams out his name.
Homs is just one of 40 besieged communities in Syria, according to the U.N.'s World Food Programme, which says about a quarter of a million people have been cut off from humanitarian aid for months.
The conflict has claimed more than 100,000 lives and displaced millions more since it began in 2011, creating a major humanitarian crisis within Syria and for its neighbors.
New Round of Peace talks
As the regime and opposition swapped accusations over the truce violations, Syria's warring sides began a new round of peace talks in Geneva.
United Nations envoy Lakhdar Brahimi met with the Syrian opposition Monday morning before separate talks with government representatives.
The second round of talks center around the formation of a transitional governmental body and the cessation of violence.
The opposition delegation said each side would meet with Brahimi separately until the U.N. envoy decided there was common ground for joint discussions.
The first round of talks ended some 10 days ago, with no firm agreements and bitter statements from both sides.
The government insists that the talks focus on fighting "terrorism" -- its description of the uprising -- but the opposition says the priority should be the removal of President Bashar al-Assad.
The opposition has insisted that the government commit in writing to the 2012 Geneva I communique, which called for the formation of a transitional government.
Al-Assad's government has ruled out any transfer of power.
Brahimi will meet with high-level Russian and U.S. diplomats in Geneva this week, the U.N. said Monday.
He will meet with Russian Deputy Minister of Foreign Affairs Gennady Gatilov and U.S. Under Secretary of State Wendy Sherman on Friday, the U.N. said without providing more details.
In a separate development, the Organisation for the Prohibition of Chemical Weapons announced a third shipment of chemical weapons material from Syria had taken place.
It said the material was on board a Norwegian cargo vessel accompanied by a naval escort from China, Denmark, Norway, and Russia.
"In-country destruction of some chemical materials has taken place alongside the removal of chemical weapons material," it added.
CNN's Salma Abdelaziz contributed to this report