Syrian government shelling and offensives against rebel-held towns killed at least 43 civilians across the country on Saturday, activists said, as the U.S. posted online satellite images of troop deployments that cast further doubt on whether the regime intends to comply with an internationally sponsored peace plan.

Syrian President Bashar Assad has accepted a cease-fire deadline brokered by international envoy Kofi Annan, which calls for his forces to pull out of towns and cities by Tuesday and for both government and rebels to lay down their arms by 6 a.m. local time Thursday.

But the escalating violence of the past few days has fueled accusations that Assad is rushing to stamp out as much of the year-old uprising against him as he can before next week's cease-fire.

The Syrian government said it has begun to withdraw forces ahead of the cease-fire but activists say no significant pullouts have taken place and troops, checkpoints and snipers remain in almost all major flashpoint towns and cities.

"They are systematically trying to crush the revolt wherever they can and regardless of the human cost," said activist Mohammad Saeed in the Damascus suburb of Douma.

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U.S. ambassador to Syria Robert Ford said the Syrian government appears to have pulled back some of its forces from towns and cities but in other places has kept in place or simply shifted around troops and armored vehicles.

He said he was basing his information on satellite images before and after the alleged pullouts which were posted on the U.S. Embassy Facebook page Saturday.

Arrests, sweeps, and the artillery bombardment of opposition strongholds have continued, Ford's statement said.

"This is not the reduction in offensive Syrian government security operations that all agree must be the first step for the Annan initiative to succeed," the late Friday statement said.

"The regime and the Syrian people should know that we are watching. The regime cannot hide the truth," it added.

Ford was forced to leave Syria in February citing security concerns, and the U.S. Embassy there was closed indefinitely.

Western leaders along with the Syrian opposition have cast doubt on Assad's intentions, suggesting he is playing for time and is not serious about the plan, which aims to pave the way for talks between the regime and the opposition on a political solution.

The government has launched offensives in several parts of the country in the past few days in a desperate attempt to crush the rebels.

The Local Coordination Committees said shelling on Saturday by government forces killed at least 40 people in central Hama province, most of them in the village of al-Latamneh. The British-based Syrian Observatory for Human Rights put the number of deaths in al-Latamneh at 36 and said four others were killed in Tibet al-Imam. It said most were killed by shells fired as troops stormed al-Latamneh following clashes with defectors there over the past two days.

An amateur video posted by activists on the Internet showed al-Latamneh residents crying "Allahu Akbar" as they held up a small girl, apparently dead. The video also shows the bodies of several men covered in white sheets lined up on the ground.

In the nearby province of Homs, activists also reported shelling of the rebel-held areas of Rastan, Deir Baalabeh and Qusair, where they said at least three people including a mother and her son were killed.

The Observatory also said 13 unidentified bodies were found in Deir Baalabeh and ten in Hreitan in the northern province of Idlib.

U.N. Secretary-General Ban Ki-moon said the April 10 timeline "is not an excuse for continued killing." In statements made Friday, he urged the government to "immediately and unconditionally" cease all military actions against the Syrian people.

An offensive in Idlib over the past few days has triggered a massive wave of refugees who crossed the border to Turkey in the past few days with horrific accounts of mass graves, massacres and burned-out homes.

Activists have reported about 100 dead in the villages of Taftanaz and Killi, both in Idlib, in recent days.

The escalating violence has dimmed hopes that the fighting, which the U.N. says has killed more than 9,000 people, will end anytime soon. The country appears to be spiraling toward civil war -- a fearsome development that could bring a regional conflagration.

Ambassador Ford urged Assad to allow a U.N. monitoring force into the country and to give it full access to investigate the regime's compliance with the peace plan.

On Friday, a small U.N. advance team headed by a Norwegian major general, Robert Mood, met with Syria's deputy foreign minister to discuss the cease-fire plans. Mood is to set up a U.N. monitoring force with 200 to 250 members if the peace plan succeeds.