Syrian rights activists say government forces have assaulted several rebel strongholds, triggering battles that killed 13 people as Arab nations began a new diplomatic effort to end Syria's year-long conflict.

The British-based Syrian Observatory for Human Rights said Wednesday forces loyal to President Bashar al-Assad stormed the northern town of Qalaat al-Madiq Wednesday, after a siege lasting more than two weeks.

It says government troops also battled rebels in the towns of Rastan in central Syria and Daraa in the south.

The violence continued a day after international envoy Kofi Annan said Syria had accepted his peace plan for a cease-fire and a dialogue between government and rebel forces. He had urged the Syrian government to implement the plan immediately.

Arab League foreign ministers expressed support for the Annan peace initiative at a meeting in Baghdad, where leaders of the regional bloc were expected to attend a summit on Thursday.

A draft resolution prepared by the ministers for the summit's approval calls on the Assad government to stop violent attacks on the opposition and allow peaceful protests.

Iraqi Foreign Minister Hoshyar Zebari said Syria's implementation of Mr. Annan's plan is “more important than acceptance” and represents a “last chance” for the country to resolve its crisis peacefully.

A Syrian official said his government will reject any resolution passed by the Arab League on Syria. The bloc suspended Syria's membership last year to punish Damascus for continuing a deadly crackdown on an opposition uprising.

Western diplomats and Syrian opposition figures reacted skeptically to Syria's acceptance of the Annan proposals. Opposition members accused Mr. Assad of trying to stall for time as his troops make a renewed push to crush dissent.

In another development, several hundred exiled Syrian opposition figures ended a meeting in Istanbul on Wednesday by declaring the Syrian National Council to be the “formal interlocutor and formal representative of the Syrian people.” Most of the participants signed on to the declaration. Some dissidents walked out of the talks on Tuesday, accusing the SNC of not listening to differing views about how to end decades of autocratic government in Syria.

The United Nations said Tuesday the number of people killed in Syria's crackdown has risen to more than 9,000, an increase of about 1,000 over the world body's previous estimate.