Fighting in Ivory Coast continued Tuesday as heavy gunfire rang out near the presidential palace in the main city of Abidjan.
Forces backing internationally recognized president Alassane Ouattara have pushed toward the few remaining strongholds of incumbent president Laurent Gbagbo as they seek to oust the defiant leader.
The United Nations mission in Ivory Coast said Monday U.N. helicopters fired on two Gbagbo army camps, the presidential palace and Gbagbo's residence.
France says its forces took part in the attack at the U.N.'s request. French President Nicolas Sarkozy ordered French troops to protect civilians and remove Gbagbo's heavy artillery.
Gbagbo supporters say the U.N. and French attacks were illegal and amounted to an assassination attempt against the incumbent leader.
U.N. Secretary-General Ban Ki-moon says the attacks were meant to prevent the use of mortars and other heavy weapons against civilians and U.N. peacekeepers. He says the military operation does not mean the U.N. is taking up arms against Gbagbo.
U.N. peacekeeping chief Alain Le Roy says he hopes the operation would be quick, and that it may be finished by Tuesday.
Ouattara's prime minister, Guillaume Soro, has promised a "lightning offensive" against Gbagbo troops. Pro-Ouattara forces have swept across Ivory Coast in the past week, but Gbagbo still has a band of loyalists who have surrounded the presidential palace, where he is believed to be.
Gbagbo refused to give up power after Ouattara was named the winner of last November's presidential election.
The United Nations, the African Union and other international bodies have demanded that Gbagbo step down so Ouattara can assume office.
The U.N. has accused Gbagbo troops of killing Abidjan residents and wounding several peacekeepers.
On Monday, the U.S. ambassador to the United Nations, Susan Rice, condemned the violence against civilians and peacekeepers in Ivory Coast. She said she supports efforts by the U.N. mission in the west African country to use all means to protect civilians.
Hundreds of people have died in post-election fighting, including many civilians. The International Federation of the Red Cross says at least 800 people were killed in the western city of Duekoue, which pro-Ouattara fighters seized last week.
The U.N. says up to 1 million people have fled their homes since violence began in December. More than 100,000 have fled to neighboring Liberia, with smaller numbers going to Ghana.
Gbagbo has ruled Ivory Coast since 2000.
Some information for this report was provided by AP, AFP and Reuters.