(CNN) -- Despite fresh violence and global skepticism, the Syrian government said Wednesday it will abide by the terms of a United Nations-backed peace plan and meet a looming deadline to halt all military action.
However, statements from Damascus said the government maintains the right to respond to opposition attacks.
Under the plan brokered by special envoy Kofi Annan, Syrian forces must silence their guns as of 6 a.m. Thursday.
But Jihad Makdissi, a Syrian foreign ministry spokesman, told CNN it will take more than Syrian forces to stop the violence. He said the presence of U.N. observers on the ground will be essential to verify the cessation of violence.
"We are not afraid of the reality of the Syrian story," he said. "We want them to be on the ground and see for themselves who is violating this.
"We are fully committed to have a successful mission for Mr. Annan, but at the same time people should know that I can say optimistically that 40% of the keys to solve the crisis is in our hands as government, but the other 60% is in the hands of those who are harboring, channeling weapons, instigating in the media against Syria," he said.
Susan Rice, the U.S. ambassador to the United Nations, offered a different assessment Wednesday.
"The burden remains squarely on the Syrian regime and not the opposition, in the first instance, to meet its obligations in full and visibly under the Annan plan," she said.
President Bashar al-Assad has insisted throughout the Syrian crisis that armed terrorist groups have been responsible for fomenting violence within the country.
Opposition groups, however, cite deaths daily at the hands of al-Assad's forces. Wednesday was no different.
Grim images and activist reports showed government forces attacking civilians in several cities and towns across Syria. The death toll rose as the day wore on. At least 98 people were killed Wednesday, said the Local Coordination Committees, or LCC, an opposition network across Syria.
Annan remained optimistic that the Thursday cease-fire would hold, though many remain skeptical of al-Assad's intentions, especially after a surge in bloodshed that has occurred since he agreed to a timetable for peace.
A fighter from the Free Syrian Army, composed mainly of defected members of the military, said the rebels will hold their fire, if al-Assad does. But that was impossible, the fighter said.
"Bashar al-Assad cannot withdraw tanks from the cities and towns, because if he does, the whole country will come out and protest against him and he won't tolerate that," said the fighter, who did not want to be identified for security reasons.
Earlier, Annan was in Iran to muster support for what had seemed like a faltering peace plan and said, "We should see a much improved situation on the ground."
Annan received a letter from the Syrian Foreign Ministry with assurances from the government that it would adhere to the cease-fire, but it was also conditional.
The ministry informed him that it reserved "the right to respond proportionately to any attacks carried out by armed terrorist groups against civilians, government forces or public and private property," according to a statement from Annan's spokesman, Ahmad Fawzi.
Opposition activists have called on the international community to arm Syrian rebels, who are clearly outmatched in strength by government forces.
"The solution is to arm the Free Syrian Army with high-quality weapons," Homs resident Saif al-Arab said about the rebel fighting force, made up mainly of military defectors.
"They are still using Kalashnikovs and light rocket-propelled grenades against the regime's military tanks," he told CNN.
Annan, however, warned against militarization, insisting that the issue has to be resolved through diplomatic channels and calling on governments in the region and beyond to work with Syrians.
"Any militarization of the Syrian issue will be disastrous," Annan said at a joint news conference with Iranian Foreign Minister Ali Akbar Salehi.
Salehi said Iran supported Annan as long as his mission did not endorse the idea of regime change in Damascus, Iran's state-run Press TV reported. Meanwhile, Iranian President Mahmoud Ahmadinejad warned regional governments not to supply weapons to opposition groups in other countries, alluding to the situation in Syria, the semi-official FARS news agency reported.
"If you send your money to pay for weapons and supply guns and disturb (the security of) other states, you should know that some day the arrogant powers may do the same to you," he said, according to FARS.
Syria's anti-government protests erupted in March 2011, followed by the bloody government crackdown.
The United Nations estimates at least 9,000 people have died in Syria since the protests began. The LCC puts the death toll at more than 11,000.
CNN cannot independently verify reports of violence and deaths as the government has severely restricted access by international media.
Al-Arab, the Homs resident, said military planes were over his besieged city Wednesday. The LCC as well as the opposition Syrian Observatory for Human Rights and Avaaz reported a heavy bombardment of Homs.
The military was also out in force in other Syrian cities and towns, activists said.
Shells rained down in Hama and government soldiers were destroying homes, according to the LCC.
Manhal Abo Baker, part of the Shaam News activist network in Hama, said his organization had filmed a series of campaigns in the besieged city.
"The videos we film make us feel sad, as nothing as changed," he said.
Tanks remained on the streets, planes were flying overhead and snipers were on rooftops, he said.
"The Annan plan will not succeed, because I do not think Assad's forces will carry out the cease-fire," al-Arab told CNN, echoing similar sentiments from other Syrians angry about what they perceive as the regime's empty promises in the peace process.
Annan himself expressed grave concerns about the situation in Syria in a letter to the U.N. Security Council after al-Assad defied a Tuesday deadline for government soldiers to withdraw from population centers.
The Syrian government said it took steps to pull back its forces, but Annan countered that while troops had moved out of some areas, they had relocated into others that were previously not targeted.
French Foreign Minister Alain Juppe said he would bring up the gravity of the situation in Syria with his counterparts at a meeting of the G8 economies that began Wednesday. Al-Assad has plainly lied to Annan, Juppe said, arguing that "what is presented as a withdrawal is in fact a thinly disguised redeployment."
U.S. President Barack Obama and German Chancellor Angela Merkel on Wednesday "shared the concern that the Assad government was not complying with the terms of the agreement negotiated by Kofi Annan and continued to engage in unacceptable brutality against its own people," the White House said in a statement describing a phone call between the two leaders.
"They agreed that this underscored the need for the U.N. Security Council to come together to take more resolute action," the statement said.
In Homs, which has borne the brunt of the regime's aggression, the LCC reported another grim discovery: a grave with 37 bodies. They were believed to have been killed the day before.
Among them were two entire families, with women and children.
CNN's Hala Gorani, Ivan Watson, Richard Roth, Jack Maddox, Amir Ahmed and Moni Basu contributed to this report.