UN, French forces attack Gbagbo bases in Ivory Coast

French and UN helicopters fired at the Ivory Coast presidential palace and bases of strongman Laurent Gbagbo as the country's elected president launched an all-out push to make him step down.The helicopters targeted the presidency, Gbagbo's residence and military barracks in the main city Abidjan, a UN official said, hours after fighters for Alassane Ouattara launched a new offensive after a months-long election dispute.

Heavy artillery fire and explosions shook central Abidjan as the offensive raged into the evening, AFP journalists reported.

"The final assault for the total capture of the residence and the palace will take place in the coming hours. The operation is expected to finish tonight," said Sidiki Konate, the spokesman for Ouattara's prime minister Guillaume Soro.

In a joint operation the United Nations mission UNOCI and former colonial power France's force Licorne (Unicorn) targeted Gbagbo strongholds.

"We launched the operation to protect people by putting heavy weapons, used by special forces of Laurent Gbagbo against people and against the UN peacekeepers, out of harm's way," said UNOCI spokesman Hamadoun Toure.

The mission was in line with UN resolution 1975, adopted on March 30 which ordered sanctions against Gbagbo and also said the UN force should protect civilians and prevent use of heavy weapons.

The joint military action followed an "urgent" request for help by UN Secretary General Ban Ki-moon in a letter to French President Nicolas Sarkozy, officials said.

"It is urgent to launch necessary military operations to put out of action the heavy arms which have been used against the civilian population and the peacekeepers," Ban wrote, according to a copy of the letter obtained by AFP.