The Syrian military has begun to fortify the Bella Valley in east Lebanon.

Witnesses say Syrian troops are digging trenches and building strongholds in mountainous regions and border areas with Lebanon near the valley.

Meanwhile, UN Secretary-General Kofi Annan says he will send his envoy Terje Roed-Larsen back to the Middle East to press Syria on its troop withdrawal from Lebanon under relevant Security Council resolution.

In a related development, Egyptian President Hosni Mubarak has met with visiting Saudi Foreign Minister Saud al-Faisal in a bid to ease the crisis over Lebanon.

Earlier, Qatar indicated it was ready to mediate between Syria and the US.