BEIRUT - The already tight security measures around bases manned by the United Nations forces in southern Lebanon (UNIFIL) witnessed 'tighter measures' Monday, following a threat by al-Qaeda chief Osama bin Laden, a Lebanese security source told Deutsche Presse-Agentur dpa.

The adopted measures came a few hours after the chief of the Sunni fundamentalist terrorist group al-Qaeda in a 56-minute voice recorded message late Saturday criticized the Lebanese Shiite Movement and its leader leader Hassan Nasrallah for allowing 'crusader' troops from the United Nations into Lebanon after its 33-day conflict with Israel in 2006.

According to an expert in fundamentalist affairs who requested anonymity, 'this statement by bin Laden should be taken very seriously because it could be a prelude to future attacks on the UN forces in southern Lebanon.'

UN troops deployed in South Lebanon were beefed up to almost 13,000 under UN Security Council Resolution 1701 which ended the 33- day war between Israel and Nasrallah's Hezbollah movement in July- August 2006.

According to a Lebanese security source in southern Lebanon, 'the UNIFIL command have been taking precautions and tight security measures around their bases in southern Lebanon before this message by al-Qaeda, but extra precautions and tighter measures were adopted following the message.'

'Even in their daily patrols, they are being very cautious,' he added.

The source said even UNIFIL cars and patrols when entering the UN bases 'are being searched thoroughly and IDs of troops riding in the UN vehicles are being checked as well.'

UN sources made no comment on the bin Laden statement. -DPA