The U.N. observer mission is tasked to monitor the cease-fire and the peace plan.

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Meanwhile, the mandate of the U.N. observer mission that had been tasked to monitor Annan's six-point peace plan, which included a failed ceasefire, ends on Sunday.

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Last month, the United Nations wound up the observer mission that had been tasked with monitoring the ceasefire in Syria under the six-point peace plan negotiated by Mr Annan.

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In a news conference a few hours before the extension to the observer mission was announced, Mr Muallem had drawn a distinction between the mission and the new Arab League peace plan announced on Sunday, he adds.

BBC: Syria agrees to extend Arab League observer mission