Even as it continued widespread shelling of opposition strongholds Wednesday, the Syrian government told peace envoy Kofi Annan that it will stop military action against rebels on Thursday morning.

In a letter to Mr. Annan, the Syrian foreign ministry said the government reserves the right after the cease-fire deadline to continue responding to attacks from “armed terrorist groups.”

The U.N.-Arab League envoy brokered a six-part peace plan last month that called for Syria's government to withdraw its forces from major urban areas by April 10 and stop combat operations by Thursday. The Syrian government agreed to the plan, which also called for opposition forces to stop fighting.

The Syrian government said it began a phased withdrawal Tuesday. But opponents say government shelling and attacks have not ceased in many areas.

Rights groups and activists say at least 11 people were killed Wednesday as government forces pounded targets in flashpoint opposition areas including the central Homs region and Damascus suburbs.

Western diplomats Tuesday slammed the Syrian government for its continuing crackdown.

Syrian Network for Human Rights chairman Mousab Azzawi says the Syrian government has continued efforts to punish dissenters, in spite of its promises to the international community.

“The regime is just using the tactics to create some kind of very hard mass punishment for those people.”

Azzawi told VOA on Wednesday that Mr. Annan should admit that his peace initiative has failed.

“Everything he has been promised by the regime, the regime just tries to find a loophole in the initiative and tries to empty the initiative.”

U.S. Secretary of State Hillary Clinton said she will again try to convince Syrian ally Russia that the situation in Syria was “deteriorating” and that the chances of a regional or civil war were increasing. She is due to meet with Russian Foreign Minister Sergei Lavrov later Wednesday in Washington.

The United States and its Western partners have pressed for stronger action against Syria for months but have been hindered by Russian and Chinese opposition to what those two nations call outside interference in Syria.

Russia said Wednesday that since the Syrian government had pledged to halt its offensive on Thursday, it was now the armed opposition's turn to do the same.

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