Israel has stepped up its offensive in the Gaza Strip, killing three more Palestinian fighters in air raids.

Two fighters from the al-Aqsa Martyrs Brigades were also killed by Israeli air raids in Nablus, in the occupied West Bank on Thursday.

 
The deaths came a day after an intensified Israeli military operation killed 15 Palestinians and damaged Hamas-run government buildings in the Gaza Strip.

Meanwhile, Hamas fired 40 rockets into Israel, killing one Israeli and wounding another on Wednesday.
 
 
Hospital officials said a fighter from Hamas and two from the Popular Resistance Committees (PRC) group were killed on Thursday.
 

The Israeli military confirmed the attack, saying they hit command posts and weapons manufacturing and storing sites.
 

Ehud Olmert, the Israeli prime minister, said on a visit to Japan on Thursday that Israeli assaults on Gaza would continue.
 

"We are at the height of this battle and we will pursue it until the danger threatening residents in the south ends.

"It is a painful process. We are taking painful blows and we will hit back with even more painful blows."

Baby killed
Israeli aircraft fired missiles at the Hamas-run interior ministry and the office of Ismail Haniya, the ousted prime minister from Hamas, late on Wednesday.
 

That attack killed Mohammed Bourai, a 6-month-old baby boy, and left many others wounded, hospital officials said.
 

A Palestinian security source said another Israeli helicopter had fired on a metals workshop in the east of Gaza City late on Wednesday.
 

Earlier, five senior members of Hamas were killed when the vehicle in which they were travelling was attacked from the air near the southern Gaza town of Khan Younis, medical officials said.
 

Hamas said the five were members of the Izz al-Din al-Qassam Brigades, its armed wing.
 

Two missiles directly hit the minivan they were travelling in, witnesses told Al Jazeera.
 

Moaiya Hassanain, a Gaza health ministry official, said four other people were wounded in the attack.
 

A spokeswoman for the Israeli military confirmed that it had "carried out strikes on vehicles in Khan Younis and identified hitting them".

HEYET Net- Agencies