Three injured in explosion at Palestinian security service's office

The offices of a Palestinian security service in Ramallah have been hit by an explosion which injured three officers.

There has been no explanation for the cause of the blast.

Witnesses said the blast went off inside the offices of Force 17, blowing off part of the roof of the building.

A Palestinian security official said the building had been struck by an Israeli helicopter gunship, but other Palestinian security officials disputed this claim.

The Israeli army said it was not involved.

Force 17 had been using one suite in the building, a former restaurant, for about a week, and only a few officers had been stationed there. Immediately after the blast, several gunmen angrily fired in the air and scuffled with each other.

Palestinian police confiscated film from photographers and TV crews and deployed officers at photo labs to prevent images from being developed, suggesting that the explosion might have been an internal matter.

Residents of the area said an explosion was also heard in the area on Wednesday, but caused no damage, and afterwards, Palestinian security officials arrived and tried to calm bystanders by saying a gun had gone off.

The blast came after a day of heavy Palestinian mortar fire on Israeli targets in the Gaza Strip, and Israeli officials pledged to respond to the continued violence.

Israel has accused Force 17 of playing a central role in shootings at Israelis traveling on West Bank roads, and has targeted Force 17 installations in the past.