A suicide bomber wearing a police uniform has killed at least 14 people, including four police officers and three NATO soldiers, in the eastern Afghan city of Khost, ISAF and local officials say.

More than 60 other people were injured in the powerful explosion, which took place in a crowded market place, hospital officials said.

Witnesses said the target was a joint foot patrol of NATO and Afghan security forces travelling near the police headquarters on Monday. The bomber struck after the soldiers and police got out of their vehicles to walk through the market area in Khost.

"Today at around 8:30am (local time; 04:00 GMT) a suicide bomber on a motorcycle targeted a joint patrol in Khost city in a crowded area," the provincial governor's office said in a statement.

An ISAF spokesperson confirmed that three NATO service members had been killed, but that details of the incident were still unclear. The deaths take coalition fatalities to at least 347 this year.

The Taliban have claimed responsibility for the attack.

The dead included a NATO-contracted interpreter and six civilians, Al Jazeera's Bernard Smith reported from Kabul.

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The provincial governor's office said that the commander of the local rapid reaction police force was among the dead.

Coalition spokesperson Major Adam Wojack would only confirm that three NATO service members and their translator were killed in a bombing in the east, without giving an exact location or the nationalities of the dead.

The international military alliance usually waits for individual nations to announce details on deaths. It was not immediately clear if the translator was an Afghan citizen or a foreigner, Wojack said.

The explosion came a day after NATO announced that a firefight between coalition troops and their Afghan allies killed an ISAF soldier, a civilian contractor and three Afghan army troops in circumstances that remained unclear.

That incident was initially described as a suspected "insider attack", but it was later suggested that either insurgent fire or a verbal argument between the troops led to the shooting.

Source: Al Jazeera and agencies