Media playback is unsupported on your device Media caption Caroline Wyatt reports: ''Security here was seen as tight''

A number of Afghan officials have been suspended as an investigation is carried out into a suicide bomb and gun attack in Kabul that killed 21 people.

The Taliban has admitted targeting a Lebanese restaurant, leaving 13 foreigners and eight Afghans dead.

Among the victims were a local IMF head and Canadian, American, UK, Lebanese, Russian and Danish citizens.

The Afghan interior minister has warned security officials in the capital that negligence will not be tolerated.

Kamal Hamade, owner of the Taverna du Liban, made the best chocolate cake, the best Lebanese food and, he thought, the best evacuation plan. The plan wasn't good enough to save him and other foreigners and Afghans who died with him when the Taliban came. But it did save many lives. I know from my own visits when in Kabul that Kamal did everything possible to make his restaurant a home away from home. Whatever food you ordered, he brought double the amount. He proudly introduced us to Afghan chefs he trained to make Lebanese specialties and Afghan guards who kept his place safe. We talked about his native Lebanon, his risky time in Baghdad, but most of all, his commitment to his new home. Now his doors are destroyed and, with them, a little of the hope that Kabul can ever be the safe inviting place he wanted the Taverna to be. Lyse Doucet: Owner dies defending restaurant Britons die in blast

Mohammad Omar Daudzai told Afghan TV that the head of the precinct in which the attack took place, and two other officials had been suspended. "They will be investigated as part of a probe into the incident that took place last night."

A suicide attacker detonated his explosives outside the gate of the heavily fortified Taverna du Liban, Deputy Interior Minister Mohammad Ayoub Salangi said.

Two gunmen then entered the restaurant and started "indiscriminately killing" people inside, he added.

Wabel Abdallah, the 60-year-old Lebanese head of the International Monetary Fund's Afghanistan office, was killed, along with the restaurant's popular Lebanese owner, Kamal Hamade.

His restaurant, in Kabul's Wazir Akbar Khan area, had come under attack before and was considered a favourite destination for foreign nationals, diplomats and aid workers.

A Taliban statement indicated the restaurant had been targeted because it was frequented by high-ranking foreigners and served alcohol.

Media playback is unsupported on your device Media caption Ari Gaitanis UN Spokesman: "It is a very heavy day here for us"

Mr Hamade had deployed a number of measures to keep pace with security requirements from foreign and Afghan organisations, the BBC's Lyse Doucet reports. Among the other victims were

Three UN civilian staff from Russia, the US and Pakistan

The Russian national was said to have been working on kick-starting peace talks with the Taliban

Two Britons: Labour Party candidate for the European Parliament elections Del Singh and Simon Chase, reportedly serving with the EU police mission, Eupol

A Danish woman also serving with Eupol

Two Canadians - it was unclear who they were working for

At least one other American, according to the US embassy

13 Afghan nationals

UN Secretary General Ban Ki-moon condemned "in the strongest terms the horrific attack", his spokesman said.

IMF Managing Director Christine Lagarde said: "Our hearts go out to Wabel [Abdallah's] family and friends, as well as the other victims of this attack".

Image copyright AP Image caption Security forces flooded the area soon after the attack

Image copyright AFP Image caption The restaurant, in the heart of Kabul's embassy district, was popular with diplomats and foreign workers.

Image copyright Reuters Image caption The explosion wrecked the restaurant and destroyed nearby vehicles.

"I was sitting with my friends in the kitchen when an explosion happened and smoke filled the kitchen," Abdul Majid, a chef at the restaurant, told AFP news agency.

"A man came inside shouting and he started shooting. One of my colleagues was shot and fell down. I ran to the roof and threw myself to the neighbouring property."

The attackers were eventually shot dead by the security forces when they arrived at the scene.

The BBC's Mahfouz Zubaide heard the blast and gunfire from at least two kilometres away. He said the gunfire went on sporadically for about 10 minutes.

Security continues to be a major concern in Afghanistan. The last remaining contingent of Nato-led forces is due to leave by the end of the year, having handed over security to Afghan forces.

Afghan President Hamid Karzai also condemned the attack, saying in a statement that if US-led Nato forces wanted to be united with the Afghan people "they have to target terrorism".

Washington is pushing Mr Karzai to sign an agreement which would allow some US troops to stay behind after this year's withdrawal.

The Taliban told the BBC's John Simpson earlier this week that they were now back in control of large areas of Afghanistan and were confident of returning to power after Western troops left.

Our correspondent says it is hard to believe the Taliban could make a comeback as things stand, but their takeover of Kabul in 1996 was unexpected, and they could be strengthened if a weak, corrupt president is elected in April.