Pakistan protested against the killing and a possible air space violation of Islamabad during the attack. The missile had hit 10 to 15 km within Pakistani border with Afghanistan and 25 km away from Khost -- the target town.

President Clinton gave the signal for the attack at 3.30 p.m IST on Thursday, and the strike, lasting less than an hour, took place some eight hours later. The strikes were targeted at the alleged bases of Saudi Arabian-born multi-millionaire Osama Bin Laden who is said to have bankrolled the bombings of two US embassies last fortnight.

Sudan today recalled its diplomats from the US and said it would file complaints with the United Nations and the Arab League. President Omar El-Bashir said that the factory which was hit was a pharmaceutical company and not a chemical weapons facility as the US claimed.

Several people were killed or injured and 300 were missing following in Sudan's capital Khortoum. Governor of Khartoum Al Mjoub Khalifa said: ``There are dead and injured among the workers who were on the evening shift at the time of the bombing and the fate of 300 others, including pharmacists and technicians, is a mystery.''

In Afghanistan, Taliban spokesman, Wakil Akhunzada, confirmed that 21 persons had died in Thursday night's attacks. He said that the missiles had exploded at Zhawar Killi Al Badr near Khost, 150 kilometres South East of Kabul. ``It is such a callous act. They have no proof of terrorism committed by Bin Laden or the Taliban. If they were going to take such action, they should have contacted us first,'' said Akhunzada.

Akhunzada said that missiles also hit targets near Jalalabad, about 100 km east of Kabul. Three people were killed in the attack. Pakistan news agency NNI, quoting the Harkat-ul Mujahideen Group, said that five of its members were killed at the camp near Khost. Harkat ul Mujahideen, formerly known as Harkat ul Ansar, was included last year on the US state department's list of terrorist groups.

Today in Kabul, two UN workers were seriously injured when they were shot by unidentified gunmen in what is perceived as a reaction to yesterday's attack.

Pakistan said on Friday that US air strikes in Afghanistan overnight violated the territorial integrity of an Islamic country. Foreign minister Sartaj Aziz expressed ``indignation'' at the American action and said that the missile attacks by Washington were ``a matter of grave concern for the people of Pakistan.''

Aziz was addressing the Pakistani Senate Friday morning after officials and opposition members bitterly criticised the American action. Outside the parliament, over 200 demonstrators had gathered to protest and sang anti-American songs. The American flag was also burnt by students of the International Islamic University, half a kilometer away from Parliament.

Aziz in his brief address said that preliminary information revealed that the strikes at six installations in Afghanistan had resulted in the loss of innocent lives, adding that the Pakistan Government has ``expressed indignation'' at the action.

The Pakistani Foreign Office on Friday summoned the US Charge d' Affairs and lodged a strong protest. It was not yet confirmed how many missiles had hit Pakistani territory.

A Foreign Office spokesman told journalists that the US had regretted the killing of Pakistanis inside Pakistan and said it happened due to a technical error. ``It must be a technical error,'' the spokesman said while quoting the US official.

``We have just heard this explanation,'' the spokesman replied when asked if Pakistan had accepted the apology. The spokesman said Pakistan had not detected the air space violation but lodged protest on the presumption that its territory had been violated.

A Pakistan-based Afghan news service reported that at least 21 persons had been killed in the attack in the Khost region and said that the toll ``could be much higher.''

Religious parties held demonstrations all over Pakistan to condemn the American action. In Islamabad, the Jamaat-e-Islami party led a demonstration while in Karachi there were over seven different demonstrations to protest America's strikes against Osama Bin Laden. A spokesman of the Jamiat-Ulema-Islam party, which is seen to be close to the Taliban movement in Afghanistan, said that American attacks were a conspiracy against the Muslim world. Jamaat leader Qazi Hussain Ahmad said that the action by the United States ``would breed more terrorism.''

Analysts say that the Pakistan Government is taking precautions against a possible terrorist attack against foreign-owned installations and property in the country. ``We have not ruled out any such possibility,'' said a police official in Islamabad, where security in the diplomatic enclave was doubled overnight to prevent a repeat of the 1979 burning of US Embassy in Islamabad. Security at the American Centre and the American embassy in Islamabad was tight and nobody was allowed through by armed policemen.

It now transpires that Pakistan, which Washington calls a close ally and a frontal state in the US fight against terrorism, was not kept in the picture at all.

(Pakistan incidentally is one of the handful of countries that recognises the Taliban government in Kabul, which hosts and shelters Bin Laden. In fact, the Taliban is widely regarded as a puppet regime of Pakistan' s Inter-Services Intelligence.) Meanwhile, although the US officially declined to provide operational details of the strike, it is aid the missile attack on the camps in Afghanistan was launched from an American flotilla in the Arabian Sea and the Red Sea.

A submarine and several surface warships in the US Abraham Lincoln battlegroup launched some 75 Tomahawk cruise missiles from the Arabian Sea and the Red Sea. The Tomahawk cruise missile has a range of 600 to 700 miles and can carry a 1,000 Kilo warhead. Its cruise altitude is between 50 and 100 feet.

Pentagon officials, however, say they have no information yet on the missile that is said to have strayed into Pakistan.

Meanwhile, there was heightened alert at US installations and establishments all over the world, including in Washington, against possible retaliatory attacks. Government establishments in Washington saw extra security precautions with what was called a threat perception alpha -- a general alert against terrorism -- in force.