We will maintain our right to continue the jihad [holy war] and resistance until the last drop of blood in our veins

Islamic Jihad

Both groups have carried out a wave of suicide attacks against Israel, prompting the Palestinian Authority to arrest scores of militants.

Hours before Islamic Jihad's announcement, Israeli troops demolished dozens of buildings in the Gaza Strip which Israel said had been used for shelter by Palestinian gunmen.

In its statement, the al-Quds Brigade - Islamic Jihad's armed wing - said it was "not bound by any agreement or co-operation with the Palestinian Authority as far as the ceasefire with Israel is concerned", Qatar-based al-Jazeera television reported.

Tentative truce

Islamic Jihad has not carried out any major attacks since it suspended suicide bombings on 21 December last year.

The Palestinian Authority has taken steps against Islamic Jihad

Five days earlier, Palestinian leader Yasser Arafat, under intense international pressure, had publicly called for an end to armed attacks against Israel.

Palestinian security forces in the Gaza Strip began rounding up scores of militants and closed down offices belonging to Islamic Jihad and Hamas.

On Sunday, Palestinian police arrested six members of Islamic Jihad in the West Bank town of Jenin, including one of Israel's most wanted suspects.

Bigger threat

The BBC's correspondent in Jerusalem says Islamic Jihad is a small group with very little public support and is not a big threat to Mr Arafat.

He is more concerned about the bigger movement, Hamas, which is very popular.

Hamas' attack followed a significant drop in violence

It appeared to break its ceasefire, also declared on 21 December, when two of its members killed four Israeli soldiers at an army outpost in southern Israel on Wednesday.

Hamas said the attack was in revenge for Israel's capture on Sunday of a ship carrying 50 tons of weapons which, Israel says, was destined for the Palestinian Authority.

However, a Hamas official insisted the group's position had not changed.

He said Hamas had agreed only to suspend suicide and mortar attacks, not all military operations.

A spate of Hamas suicide attacks in Jerusalem and the northern Israeli city of Haifa in early December killed 26 people and injured dozens more, sparking fierce Israeli retaliation.

The latest surge in violence came after three weeks of relative calm between Israel and the Palestinians and has dealt a severe blow to US efforts to implement a ceasefire.