UNITED NATIONS - The chief United Nations observer in Syria, Major General Robert Mood, is expected to brief the UN Security Council on the current situation in Syria on Tuesday afternoon as violence was intensified by both sides in the Middle East country, diplomats and UN officials told Xinhua here Monday.

Mood, who is head of the UN Supervision Mission in Syria ( UNSMIS), is to brief the 15-nation Security Council at around 4 pm (2000 GMT) on Tuesday, they said.

The upcoming briefing will come about three days after Mood announced that UN observers had suspended their monitoring activities owing to an intensification of armed violence across the country in recent days.

On Sunday, Mood, who is from Norway, has appealed to the parties to enable civilians trapped by the escalating violence to leave conflict zones.

"The parties must reconsider their position and allow women, children, the elderly and the injured to leave conflict zones, without any preconditions and ensure their safety," Mood said in a statement issued on Sunday.

"This requires willingness on both sides to respect and protect the human life of the Syrian people," he said.

The Security Council established UNSMIS in April to monitor the cessation of violence in Syria, as well as monitor and support the full implementation of a six-point peace plan put forward by the joint special envoy of the United Nations and the Arab League for the Syrian Crisis, Kofi Annan.

The plan calls for an end to violence, access for humanitarian agencies to provide relief to those in need, the release of detainees, the start of inclusive political dialogue that takes into account the aspirations of the Syrian people, and unrestricted access to the country for the international media.

The UN estimates that more than 10,000 people, mostly civilians, have been killed in Syria and tens of thousands displaced since the uprising against President Bashar al-Assad began some 16 months ago.