French soldiers walk past a hangar they are staying at the Malian army air base in Bamako. France plans to increase its troops in Mali to 2 500 in the days ahead and is working to speed up the deployment of West African troops for a campaign against Islamist rebels, the government said on Monday.

Bamako/Paris - Al-Qaeda-linked Islamist rebels launched a counteroffensive in Mali on Monday after four days of French air strikes on their northern strongholds, seizing the central town of Diabaly and promising to drag France into a brutal Afghanistan-style war.

France, which has poured hundreds of troops into the capital Bamako in recent days, carried out more air strikes on Monday in the vast desert area seized last year by an Islamist alliance grouping al-Qaeda's North African wing AQIM alongside Mali's home-grown MUJWA and Ansar Dine militant groups.

“France has opened the gates of hell for all the French,” said Oumar Ould Hamaha, a spokesperson for MUJWA, which has imposed strict sharia, Islamic law, in its northern fiefdom of Gao. “She has fallen into a trap which is much more dangerous than Iraq, Afghanistan or Somalia,” he told Europe 1 radio.

Paris is determined to shatter Islamist domination of the north of its former colony, an area many fear could become a launchpad for terrorism attacks on the West and a base for co-ordination with al-Qaeda in Yemen, Somalia and North Africa.

The French defence ministry said it aimed to deploy 2 500 soldiers in the West African state to bolster the Malian army and work with a force of 3 300 West African troops from the immediate region foreseen in a UN-backed intervention plan.

The United States, which has operated a counter-terrorism training programme in the region, said it was sharing information with French forces and considering providing logistics, surveillance and airlift capability.

“We have a responsibility to go after al-Qaeda wherever they are,” Defence Secretary Leon Panetta told reporters heading with him on a week-long tour of European capitals.

As French aircraft bombarded mobile columns of Islamist fighters, other fighters launched a counter-attack to the south-west of recent clashes, dislodging government forces from the town of Diabaly, just 350km north-east of Bamako. French and Malian troops attempting to retake the town were battling Islamists shouting 'Allahu akbar', residents said.

The rebels infiltrated the town overnight from the porous border region with Mauritania, home to AQIM camps housing well-equipped and trained foreign fighters. A spokesman for Ansar Dine said its fighters took Diabaly, working with AQIM members.

Dozens of Islamist fighters died on Sunday when French rockets hit a fuel depot and a customs house being used as a headquarters. The UN said an estimated 30 000 people had fled the fighting, joining more than 200 000 already displaced.

France, which has repeatedly said it has abandoned its role as the policeman of its former African colonies, convened a UN Security Council meeting for Monday to discuss the Mali crisis.

The European Union announced it would hold an extraordinary meeting of its foreign ministers in Brussels this week to discuss speeding up a EU training mission to help the Malian army and other direct support for the Bamako government.

French Foreign Minister Laurent Fabius said France would do everything to ensure that regional African troops were deployed quickly to follow up on the French military action, which was launched to block a push southwards by the Islamist rebels.

“We knew that there would be a counter-attack in the west because that is where the most determined, the most organised and fanatical elements are,” French Defence Minister Jean-Yves Le Drian told France's BFM TV.

France has said its sudden intervention on Friday, responding to an urgent appeal from Mali's president, stopped the Islamists from seizing the dusty capital of Bamako.

President Francois Hollande says Operation Serval - named after an African wildcat - is solely aimed at supporting the 15-nation West African bloc Ecowas which received UN backing in December for a military intervention to dislodge the rebels.

Hollande's robust intervention has won plaudits from Western leaders and has also shot down domestic criticism which portrayed him as spineless and indecisive.

Under pressure from Paris, regional states have said they hope to send in their forces this week. Military chiefs from Ecowas nations will meet in Bamako on Tuesday but regional powerhouse Nigeria, which is due to lead the mission, has cautioned that training and deploying troops will take time.

Two decades of peaceful elections had earned Mali a reputation as a bastion of democracy in turbulent West Africa but that image unravelled after a military coup in March left a power vacuum for MNLA Tuareg rebels to seize the desert north.

MUJWA, an AQIM splinter group drawing support from Arabs and other ethnic groups, took control of Gao, the main city of the north, from the Tuaregs in June, shocking Mali's liberal Muslim majority with amputation of hands for theft under sharia.

Malian Foreign Minister Tyeman Coulibaly said the situation had become “untenable” in the north. “Every day, we were hearing about feet and hands being cut off, girls being raped, cultural patrimony being looted,” he told the French weekly Paris Match. - Reuters