Fighting in Syria today.

As the United Nations-backed peace plan deadline passed today for Syrian troops to leave cities and towns, opposition activists reported continued shelling and clashes, putting the recently brokered plan in limbo.

In Turkey, special envoy Kofi Annan said there was still time to stop the violence and that the plan "is still on the table."

The plan negotiated by the former U.N. secretary general and agreed to by Syrian President Bashar al-Assad called for regime forces to pull back to their barracks today ahead of a complete ceasefire on Thursday morning.

In Moscow, Syrian Foreign Minister Walid al-Muallem met with Russian counterpart Sergei Lavrov and told reporters at a press conference that troops and weapons were in the process of being withdrawn.

"I told my Russian colleague of the steps Syria is taking to show its goodwill for the implementation of the Annan plan," said al-Muallem. "We have already withdrawn military units from different Syrian provinces."

But the opposition reported continued shelling in the restive city of Homs and near the second-biggest city Aleppo, heavy weapons and aircraft used against the southern city of Daraa, and clashes and raids elsewhere around the country.

"The United Nations' and Arab League's failure to rein in this regime and put an end to the killing, destruction, arson, and rape, is contributing to the deteriorating humanitarian situation and will likely result in this domestic conflict spilling beyond Syria's borders," read a statement from the Local Coordination Committees of Syria.

The LCC said dozens of Syrians were killed today. The reports couldn't be verified due to the restricted access the regime gives journalists.

Today's broken deadline and comments by Muallem all but erased the chances of the ceasefire the peace plan calls for at 6 a.m. on Thursday. It also lowered hopes of the realization of the other parts of Annan's six-point plan which included approximately 250 international monitors.

"The ceasefire should occur simultaneously with the arrival of the group of international observers in Syria," al-Muallem told reporters.

Lavrov called on Syria to allow the observers in and criticized its close ally for not being more pro-active in bringing about peace, the latest sign that Russia's patience may be wearing thin.

"Frankly speaking, we gave our assessment of the situation to our Syrian colleagues," Lavrov said. "We think that they could be taking more action and being more decisive in the way they carry out the plan's provisions."

Annan was visiting some of the Syrian refugee camps in southern Turkey today that house 25,000 refugees who have fled the violence. At a press conference after the visit, Annan again called for a cessation of violence, international monitors and unimpeded access for humanitarian workers.

"We still have time between now and the 12th to stop the violence," he said. "I appeal to all concerned, the government in the first place, and the opposition."

Despite Annan's high-profile attempt to stop the 13 months of bloodshed that the United Nations says has killed more than 13,000 people, expectations were low as it followed in the footsteps of other failed attempts. On Sunday, the Assad regime called for written guarantees from the armed opposition that they would lay down their weapons, which the State Department called a stalling tactic. A Syrian Foreign Ministry spokesman also said the April 10 withdrawal from cities was "a wrong interpretation."

The head of the opposition Free Syrian Army said it would not be providing written guarantees, but vowed to abide by the terms of the peace plan, a promise difficult to keep considering the lack of a real command structure. Annan said he would be writing a letter to the Security Council today, due to meet this afternoon.

"The plan is still on the table and it's a plan we are all fighting to implement," he added. "If you want to take it off the table, what would you replace it with?"