Fatah al-Islam, a suspected al-Qaeda linked Palestinian group, claimed responsibility for the two bombs that exploded in Beirut in recent days, after three days of fighting with the Lebanese army.

"As the fighting rages against the Lebanese army in the area of the camp of Nahr al-Bared, a group of heroic mujahideen has planted and blown up two explosive charges in the heart of Beirut," it said in a statement sent to foreign news agencies in Beirut.

Fatah al-Islam warned of more attacks in the capital.

"We have warned the Lebanese army, and we have now fulfilled our promise," the statement said. "We warn all those who have Western hands not to harm our mujahideen or the Sunnis in Lebanon," the statement went on, making reference to the Western-backed Lebanese government. "We will not hesitate to cut off their hands and even their heads."

Fatah al-Islam has engaged in clashes with the Lebanese army since early Sunday in the Nahr al-Bared refugee camp. Dozens of people are believed to have lost their lives in the three-day fighting.

According to a Lebanese military source, the authorities managed to stop another attempt to plant a bomb in the north-east area of Beirut called Mansouriyeh, as security forces caught a Palestinian and an Egyptian in the area who were carrying a bag full of explosives.

Abu Selim, the spokesman of Fatah al-Islam, said that a ceasefire went into effect at 2:30 local time.

"The ceasefire went into effect 2:30 pm to allow the evacuation of the wounded and to allow humnaitarian supplies to enter the camp," Abu Selim told dpa by phone. "This is not a truce...this is a ceasefire," he said.