Nearly 130 people were reported killed across Syria on Saturday, 86 of them civilians, as regime forces pressed a protest crackdown three days ahead of a deadline to cease fire and pull back.
Monitors reported the escalation in violence despite UN chief Ban Ki-moon's latest rebuke to Damascus for stepping up its assault on dissent hubs ahead of Tuesday's deadline.
At least 40 civilians died "in bombardment and shooting on the town of Latamna," in Hama province, said the Britain-based Syrian Observatory for Human Rights monitoring group.
Five civilians were killed as well in Tibet al-Imam, also in Hama, while another 18 died in the neighbouring province of Homs, where Rastan town was bombed, 22 in Idlib to the northwest, and one in Aleppo in north Syria.
A Lebanese bus carrying Shiite pilgrims was caught up in a deadly clash between rebels and troops inside the Syrian border on Saturday, the Observatory and a Lebanese television station reported.
Al-Manar television of Lebanon's Shiite movement reported one person killed and three wounded when a rocket hit the bus carrying pilgrims from Syria to Iraq. The violence occurred near the rebel town of Qusayr.
The latest reported deaths came after President Bashar al-Assad's forces launched an overnight assault on Latamna and clashed with members of the rebel Free Syrian Army.
UN-Arab League envoy Kofi Annan has warned of "alarming" casualties as the Syrian government's year-long crackdown on dissent -- which the United Nations says has killed more than 9,000 people -- showed no signs of abating.
Monitors put the number of dead at more than 10,000.
On Saturday, rebels attacked a military intelligence headquarters in the second city of Aleppo, the Observatory said, and army deserters also pressed a dawn assault on Ming air base in the same province.
Fighting was also reported between troops and deserters in districts of Hama city.
"Regular forces launched an assault early on Saturday on the Al-Qussur district, where they burned down the house of an activist," said an activist on the ground, Abu Ghazi al-Hamwi.
The Local Coordination Committees group, which organises protests at a local level, on Saturday posted online videos of tanks and armoured cars deploying in Douma, just north of the capital.
Thousands of people demonstrated in Damascus on Saturday in support of the ruling Baath party on the 65th anniversary of its creation, an AFP journalist said.
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The official SANA news agency reported similar demonstrations in other cities that "expressed the Syrian people, army and leadership's steadfastness in the face of the conspiracy hatched against Syria."
Ban said on Friday that the increased attacks by Assad's forces on cities "violate" a UN Security Council statement demanding an end to hostilities by Tuesday's truce deadline.
He indicated that he believes Assad's government is using the deadline to pull troops and heavy weapons away from cities as "an excuse" to step up the killing.
Ban "deplores the assault by the Syrian authorities against innocent civilians, including women and children, despite the commitments by the government of Syria to cease all use of heavy weapons in population centres," said his spokesman Martin Nesirky.
"The April 10 timeline to fulfill the government's implementation of its commitments, as endorsed by the Security Council, is not an excuse for continued killing," Ban added.
The Security Council passed one statement backing Annan's peace plan and on Thursday agreed a second "presidential statement" formally endorsing the April 10 limit for Syrian troops and big guns to be withdrawn from cities.
Russia and China, which vetoed two Security Council resolutions on Syria, have signed up to the new demands.
But Syria said on Friday that the number of what it calls "terrorist acts" has risen since the deal was reached with Annan.
"The terrorist acts committed by the armed terrorist groups in Syria have increased during the last few days, particularly after reaching an understanding on Kofi Annan's plan," it said in a letter to Ban.
At the same time, Damascus lashed out at the UN high commissioner for human rights, Navi Pillay, accusing her of turning a blind eye to "terrorism" funded from abroad.
Damascus has also demanded a written commitment that the opposition will not seek to exploit the troop withdrawal to make territorial gains.
Meanwhile, Syria's Foreign Minister Walid Muallem is scheduled to travel to Moscow on Monday for talks.
Elsewhere, Turkey said on Saturday nearly 700 Syrian refugees poured across the border in 24 hours, bringing to more than 24,000 the total number of Syrians seeking haven there.
And the Organisation of Islamic Cooperation said at least one million people inside Syria affected by violence need urgent humanitarian aid worth $70 million, following a joint OIC-UN visit to assess the country's needs.