Tensions wound tight in Mid-East

Israeli troops said they stopped a boy wearing an explosives belt

Israeli tanks have carried out a second incursion into the Palestinian refugee camp of Khan Younis.

A policeman was injured when an Israel gunship fired a missile at a police post, Palestinian residents said.

On Wednesday, the Israeli army said it had arrested a young boy wearing a explosive belt at a checkpoint.

Tensions have risen dramatically since Monday, when Israel assassinated the paraplegic spiritual leader of militant group Hamas, Sheikh Ahmed Yassin.

On Wednesday, remaining Hamas leaders reiterated pledges to avenge the killing.

Sharon targeted

"We are carrying out our duty to defend our families and ourselves," the group's new overall leader, Khaled Mashaal, told reporters in the Syrian capital Damascus.

"Any target that the mujahideen [Islamic holy warriors] are able to reach will not be spared," he said.

Mashaal: backed away from earlier reported Hamas threats to the US

Asked in an interview with Reuters if Israeli Prime Minister Ariel Sharon was a target, he said: "It is the right of the resistance to target the leaders of the enemy, the heads of Zionist terrorism... it is a matter of duty and right."

But he insisted all actions would be confined to "the land of Palestine" - distancing himself from earlier apparent threats from Hamas' military wing that it would target US citizens and interests.

Meanwhile, Israeli tanks and helicopter gunships moved into the camp of Khan Younis for the second time in two days.

Homes bulldozed

A missile was fired in response to Palestinian gunfire, said Israeli military sources. Palestinian sources said the missile had injured a policeman.

Israeli bulldozers reportedly demolished more buildings in the camp before moving out.

Earlier on Wednesday a boy - thought to be in his mid-teens - was stopped at a crossing near the town of Nablus wearing a belt of explosives.

An Israeli spokeswoman said he had been running towards security forces, but stopped when they pointed their guns at him.

The bomb was destroyed by Israeli army sappers.

The boy's brother told AP he suffered developmental problems and "has the intelligence of a 12-year-old".

UN resolution

The assassination of Sheikh Yassin was denounced by several world leaders and is now the subject of a resolution before the UN Security Council.

A resolution has been put to the Council by Algeria, condemning what it calls the extra-judicial execution.

The resolution also condemns all terrorist attacks against civilians.

The vote on this latest resolution is expected to take place at 2100 GMT on Thursday.