At least 100 people were reported killed across Syria Saturday, as government forces pounded opposition strongholds three days ahead of a deadline to halt all military action.

The Syrian Observatory for Human Rights, a group that tracks the violence in Syria, said about two-thirds of those who died were civilians and that many of the casualties were in the central village of Latamneh.

Rights groups and witnesses said military shelling and clashes between pro-government and opposition forces erupted in several regions.

Ausama Monajed, a spokesman for the opposition Syrian National Council, said the government was trying to crush dissent ahead of the April 10 deadline.

“We've seen this over and over again. This will never bear any fruit and the regime will always try to escalate the level of violence before any deadline.”

Also Saturday, thousands of Syrians rallied in Damascus and several other cities to mark the 65th anniversary of the creation of the ruling Baath Party. Many waved red, black and green Syrian flags or pictures of President Bashar al-Assad.

The Syrian government has promised to stop all military action by April 10 under terms of a peace agreement brokered by U.N.-Arab League envoy Kofi Annan. The agreement calls for the opposition to lay down its arms within 48 hours after the government fulfills its promise.

Monajed says the Syrian National Council backs the peace plan but doubts President Assad will abide by its provisions.

“Despite the fact that we supported the plan — and we still do — we do not think it is going to bear any fruit.”

U.N. Secretary General Ban Ki-moon on Friday sharply criticized the Assad government for its continued assault on civilians and said the cease-fire deadline “is not an excuse for continued killing.”

The U.N. says more than 9,000 people have been killed in Syria since the uprising began 13 months ago.