A suicide bomber blew himself up at an Afghan hotel close to a historic mosque in Pakistan's northwestern city of Peshawar on Tuesday, killing at least 26 people, including two women and a child, and injuring scores.

Security officials suspected that the attack was aimed at the Uzbek-origin owner of the four-story Marhaba hotel, who also died in the blast which occurred at 12.30 pm in the ground floor of the restaurant in the capital of North West Frontier Province.

Hours after the explosion, Pakistan's Interior Secretary Kamal Shah said a note recovered from the blast site said the attack was aimed at 'agents'.

Provincial Police Chief Sharif Virk also said that investigators found the legs of the suicide bomber, with a message taped to one of the legs that said the spies for the US would meet the fate of those killed.

Shah was quoted as saying by the private Geo TV that police suspected the target of the attack was Haji Sadiruddin, the owner of the hotel.

The restaurant was famous for its Afghan cuisine and exclusively catered to requirements of tribals from south and north Waziristan, where Taliban members targeted foreign militants specially Uzbeks. A large number of Uzbeks have been killed in the counter-attacks by local Taliban.

NWFP Chief Minister Muhammad Durrani said 26 people died in the blast, which came two days after the killing of top Taliban Commander Mullah Dadullah, whose outfit also had close links with both the tribal agencies of Pakistan, where al-Qaeda too was active.

Marhaba restaurant was located at the crowded Naz Cinema Road close to the centuries-old Mahabat mosque in Peshawar. The blast took place during the lunch time when a large number of people were in the hotel, which was completely damaged.

Additional Inspector General of NWFP, Fayaz Taru, told Geo TV that four to five kg of explosives mixed with nuts and bolts were used in the blast.

Reports from Peshawar said most of those killed were Afghan refugees and included two women and a child. Local Nazim, Ghulam Ali, said 25 injured persons were rushed to the local Lady Reading Hospital, where an emergency had been declared to treat the wounded.

The blast took place just as President Pervez Musharraf completed his address in Islamabad to the meeting of Foreign Ministers of the Organisation of Islamic Conference. The two-day-conference inaugurated by Musharraf is being attended by the Foreign Ministers and officials from 57 Islamic countries.

A red alert had also been announced in the violence-hit southern port city of Karachi to check any terrorist act, police officer Azhar Farooqi said.

Authorities in Punjab province also declared security alert after the Peshawar blast, TV channels reported.

Tuesday's blast came as political tension gripped Pakistan for the past few days, specially after a wave of violence in Karachi for three days from May 12 in which over 40 people were killed.

The entire country was shut down on Monday in response to a general strike called by the opposition parties to protest against the denial of permission to suspended Chief Justice Iftikhar M Chaudhry to go out of the Karachi airport to attend a convention of lawyers on May 12.

Body parts littered the road outside the hotel and television footage showed badly mutilated bodies of the victims on stretchers being taken to the hospital on ambulances.

An employee of the hotel told reporters that the three sons of the restaurant's owner, an Afghan refugee, were also killed in the blast.

Durrani announced a compensation of Rs 1 lakh for the families of the victims as police evacuated the hotel and cordoned off the scene.

Some security analysts in Pakistan pointed out that Tuesday's blast -- that too near the crowded hotel frequented by tribals -- took place just days after the killing of prominent Taliban commander Mullah Dadullah by Afghan and coalition forces in Afghanistan. Taliban has confirmed the loss of Daduallh, the one legged militant who had reorganised Taliban in Pakistan's tribal areas.

Pakistan's Interior Minister Aftab Khan Sherpao and his son had survived a suicide bomb blast at Charsadha in NWFP last month in which 30 people were killed.

Peshawar, a city near Afghan border, has witnessed periodic bomb attacks in recent years. In January, a suicide bombing near a Shiite mosque killed 15 people and wounded more than 30.

Attacks on people suspected of spying for the US forces across the border in Afghanistan have escalated in recent months, especially in the tribal areas.