Israeli military sources said they shot dead one fighter and were chasing another who tried to infiltrate the Kfar Darom settlement in the central sector of the coastal strip on Sunday.
Palestinian witnesses heard at least two explosions caused by mortars being fired by fighters at the settlement, but apparently there were no injuries.
Earlier on Sunday, a Palestinian resistance fighter was killed and another injured in an exchange of fire with Israel occupation troops in the northern West Bank town of Jenin.
Up to 15 others, including activists, were detained during the invasion by Israeli troops into the city and refugee camp which began at midnight on Saturday.
The Palestinians identified the dead man as Ammar Ghawadra, a member of Islamic Jihad's military wing, al-Aqsa Martyrs' Brigades.
Meanwhile, hundreds of Israeli soldiers launched search operations after they surrounded the eastern district of the city, adding to other neighbourhoods already under siege for the past four days.
Aljazeera's correspondent said tens of young Palestinian men had been challenging the curfew and clashing with troops surrounding the camp.
The latest death brings the toll of
the Palestinian intifada to 3510
Scores of families have appealed via Aljazeera for humanitarian organisations to come to their aid and help relieve food shortages due to the Israeli clampdown.
The latest death brings to 4541 the number of people reported killed since the start of the Palestinian intifada in September 2000. Of the total, 3510 have been Palestinians and 957 Israelis.
In the Gaza Strip, meanwhile, an Israeli was injured early on Sunday when a mortar round was fired into the Gush Katif settlement.
Hamas's military wing, Izz al-Din al-Qassam Brigades, in a statement to Aljazeera, claimed responsibility for targeting two Jewish settlements.
The statement said they fired five mortar bombs at Kfar Darom settlement in central Gaza Strip and another one at Moraj settlement in the south.