BEIRUT - The U.S. warned Syria this weekend that it won't be able to deceive the world about compliance with a cease-fire that is just days away. Regime forces pounded more opposition strongholds on Saturday in an apparent rush to crush resistance before troops must withdraw. Activists said more than 100 people were killed, including at least 87 civilians.

Almost half died in a Syrian army raid on the central village of al-Latamneh, activists said. Amateur video from the village showed the body of a baby with bloodied clothes and an apparent bullet wound in the chest. On another video, a barrage of shells is heard hitting a neighborhood of Homs as the restive city's skyline is engulfed in white smoke.

Syrian President Bashar Assad last week accepted a cease-fire agreement brokered by international envoy Kofi Annan calling for government forces to withdraw from towns and villages by Tuesday, and for the regime and rebels to lay down their arms by 6 A.M. Thursday. The truce is meant to pave the way for negotiations between the government and the opposition over Syria's political future.

However, Western leaders are skeptical about Assad's intentions because of previous broken promises and the recent escalation in attacks on opposition strongholds, including arrest sweeps and shelling of civilian areas. The U.S. ambassador to Syria posted online satellite images late Friday that he said cast doubt on the regime's readiness to pull out. "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," Robert Ford wrote on the embassy's Facebook page.

Ford posted photos he said show the government has pulled back some forces, but kept others in place or simply shifted around troops and armored vehicles. Earlier this week, the government claimed it had withdrawn from several areas.

"The regime and the Syrian people should know that we are watching," Ford wrote, citing satellite surveillance. "The regime cannot hide the truth."

The ambassador, who left Syria in February amid security concerns, said the Syrian government must give UN monitors access to confirm its compliance with the cease-fire. A UN advance team arrived in Damascus earlier this week; Annan's spokesman has said the UN-Arab League envoy hopes to put together a team of 200 to 250 observers.

Syria says the details of the mission have not been worked out.

UN Secretary-General Ban Ki-moon, meanwhile, expressed alarm about escalating violence, saying Tuesday's deadline for a troop pullback "is not an excuse for continued killing." On Friday, he urged the regime to cease all military action immediately and unconditionally.

In Saudi Arabia, the Organization of Islamic Cooperation said on Saturday that it believes some 1 million of Syria's 23 million residents need humanitarian assistance. The OIS, which considers itself the voice of the Islamic world with 57 Muslim majority member states, said it would provide $70 million in aid, including food and medical supplies. It has already sent nine trucks with relief to the areas most in need.

Saturday's deadliest fighting was reported in al-Latamneh in the central Hama province. Regime troops stormed the village after shelling it, killing at least 40 people, according to the Britain-based Syrian Observatory for Human Rights.

In the nearby province of Homs, activists reported shelling of the city as well as the rebel-held areas of Rastan, Deir Baalabeh and Qusair.

In all, at least 87 civilians and 16 opposition fighters were killed, the group said. The Observatory said two dozen Syrian troops were also killed.

Syrian officials said troops arrested large numbers of gunmen and killed "some others" in the Damascus suburbs and in the center of the country. The government said it seized large amounts of weapons and ammunition on Saturday. The regime claims the revolt is a foreign-led conspiracy, rejecting its portrayal as a popular uprising.