West African leaders on Thursday called on the UN to strengthen the mandate of its peacekeeping mission in Ivory Coast and to impose tough sanctions against Laurent Gbagbo and his associates.

The statement followed a summit of regional bloc ECOWAS, which came three months after it had threatened the use of force if Gbagbo did not yield power in favour of his internationally recognised rival Alassane Ouattara.

Gbagbo has defied calls to step down and the country now teeters on the brink of civil war.

The bloc said in its statement it "requests the UN Security Council to strengthen the mandate of the UN Operation in Cote d'Ivoire (UNOCI), enabling the mission to use all necessary means to protect life and property and to facilitate the immediate transfer of power to Mr. Alassane Ouattara."

It also said it "requests the UN Security Council to adopt more stringent international targeted sanctions against Mr. Laurent Gbagbo and his associates."

But despite the sharply worded statement, it remained far from clear whether such measures could be approved by the Security Council. There have also been divisions within the region over whether force should be used.

Ivory Coast's crisis has meanwhile only intensified following disputed November elections, with violent clashes between pro-Gbagbo forces and those backing Ouattara.

According to the UN, more than 460 people have been killed since mid-December.

One observer said earlier Thursday that the UN is limited in taking any further action and the west African bloc lacks the ability to enforce sanctions if it were to approve them on its own.

"We're not going to see a Libya-like situation here with no-fly zones and things like that," said Alex Vines, head of the Africa programme for London-based think tank Chatham House and a former UN sanctions inspector.

"It's not good news for the average Ivorian because it means this worrying situation can deteriorate further."

He added that "I just hope they realise what a dangerous situation this is -- the leadership on all sides. There is a real danger of this becoming an open civil war."

The United Nations mission in Ivory Coast said Thursday that the west of the country was wracked by violence and confusion, and a warehouse belonging to the UN refugee agency had been looted by a group of militia.

Bloodshed has become a daily occurrence in the world's top cocoa producer, and activists have pleaded with regional leaders to act to stop the violence in the country.

The UN mission has come under fire for failing to protect civilians and Ouattara's government has urged the UN Security Council "to authorise the immediate use of legitimate force to protect civilians in imminent danger."