European foreign ministers have been summoned to an emergency meeting in Brussels on Thursday to decide how to support France's war in Mali.

They are expected to finalise plans to dispatch hundreds of EU military personnel to Bamako to train half the Malian army and appoint a head of that mission as well as a senior diplomat as an EU special representative to the Sahel.

Caught by surprise by the Islamist surge at the weekend from the north of the country, individual EU countries have been quick to offer the French logistical support, mainly in the form of transport aircraft from the Germans and the British. While the French media have largely cheered on the president, François Hollande, in what is considered to be a rare display of decisiveness in Africa, they have also showered scorn on the other Europeans, seen as failing to step up to the plate.

Senior diplomats and officials in Brussels on Wednesday admitted they had been stunned by the rebel offensive and also surprised by the Islamists' prowess, capability, assets, and level of training, while rejecting the charge of fecklessness.

"It's all happened extremely fast," said an EU military officer. "But it's the postcolonial legacy. It was always going to be a French ball."

"It's important the EU shows unity of purpose and determination in support of the Malian government," added an EU diplomat, although there was palpable dismay in Brussels at the political chaos in Bamako since last year's coup, the disarray among government forces, and the lack of progress towards elections and constitutionality. Around €230m (£190m) in EU aid is currently being withheld.

The training mission for four battalions of the Malian army or 2,600 troops – half the government forces – is expected to be launched next month, with a reconnaissance team due in Bamako this weekend. Britain is expected to supply two staff officers to the training mission. Up to 12 EU countries have offered to take part.

Senior French diplomats told their EU colleagues on Tuesday that France's initial aims in Mali were to drive the rebels back into their northern heartland, contain them there, "prevent the collapse of the Malian state", "create a political space" and slowly enable troops from the Ecowas grouping of west African states to supplant the Europeans.

The EU appears alarmed at the incipient threat posed to Mali, the wider region, and Europe by the Islamist militants.

"AQIM [al-Qaida in the Maghreb] is growing, reinforcing itself, deepening itself in the region," said another senior diplomat. "It's becoming more and more a safe haven for jihadis coming from Europe and is a threat to the EU. There is also an increasing threat to Bamako. If Bamako had fallen, the situation would have deteriorated drastically. The only way to remove the risk is to remove the threat."

The initial plan was to dispatch an army training mission of around 250, but officers involved in the planning said this would now need to be augmented by "several hundred" combat troops deployed to protect the mission.

The training would take place in a safe area north-east of Bamako and the EU troops would stay put, not venturing into the northern battle zone.

"We need to have very strong force protection," said the official. "We won't do mentoring. We won't go up north."