Afghan security forces have detained hundreds of suspects in Kabul, following Sunday's failed assassination attempt against President Hamid Karzai.

According to senior security sources in Kabul, the Afghan police and intelligence service detained some 200 guests at a cheap hotel in Kabul popular among travelling salesman. Among them were the six assailants, who launched their machine gun and grenade attack on Sunday morning, killing an MP, a Shia Muslim religious leader and an 11-year-old boy.

It emerged yesterday that one grenade exploded only 20 metres away from the VIP viewing stand, where cabinet ministers, ambassadors and senior Nato officers were assembled to watch the military parade.

Eyewitnesses reported that the attackers opened fire from the third floor of the hotel, while other guests fled to the basement for cover. All the guests are being questioned by the authorities and most are expected to be released.

Yesterday, Afghan soldiers sealed off parts of the capital while plain clothes intelligence officers conducted searches, suggesting that some of the gang might still be at large. Three of the men were killed by security forces, one wounded and three captured. The three dead have been identified. All are Afghan nationals from different provinces of the country.

So far two militant groups have claimed responsibility for the attack, the Taleban and the Hezbi-Islami group headed by the former mujahideen leader Gulbudin Hekmatyar, whose forces are fighting American troops in the east of the country.

President Karzai, who was evacuated by a parade ground where he was taking part in the country's independence day ceremony, has ordered an inquiry into why there was such a serious breach of security. One theory is that it was caused by one security team handing over responsibility for protecting the ceremony to another team on the eve of the event.

"First, it (the investigation) will investigate the plot and identify those behind the attack ... and second it will find out where the problem in providing security lay," said General Abdul Rahim Wardak, the Defence Minister, after meeting the President.

Whatever the reasons for the security breach, the attack was a blow to the government's attempts at imposing security over the capital and extending its authority across the rest of the country. It also provided the Taleban with a propaganda coup, as Afghan police and soldiers were filmed live on television fleeing the gunfire.

"There is no security force in Afghanistan that people trust," said Ramazan Bashardost, an Afghan MP. "If you pay attention to yesterday's incident, the security forces fled the area before the ordinary people did."

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