Reports by the Hamas affiliated Al-Aqsa television that the Israeli army has hit residential areas in the Zaytun district by phosphorous bombs.
The Israeli phosphorous bombs also hit a UN school in Beit Lahia in northern Gaza early Saturday. According to medics and witnesses, the strike on the school, where civilians were sheltering from the fighting, has claimed the lives of a woman and a child, injuring eleven others.
Meanwhile, several explosions were heard as the Israeli army's apache helicopters flew over Gaza and their tanks hit various locations in the outskirts of Gaza city.
The Israeli forces have also hit two more mosques in the Gaza City, press tv reported.
Different positions in the city have been targeted by Israeli forces since early Saturday.
Tel Aviv has escalated its bombing campaign on the besieged coastal strip as its ground forces met a fierce resistance from Palestinian fighters.
The Israeli military denies using the weapon against civilians, saying it is using white phosphorus shells only to create smokescreens to allow its ground forces to operate.
On January 11, Human Rights Watch announced that Israel had fired artillery shells with the incendiary agent white phosphorus into Gaza.
Since the start of the US-backed Israeli offensive against Gazans on December 27, at least 1,188 Palestinians have been killed and more than 5,300 others wounded -- a large number of whom are civilians.
Tel Aviv says it launched the aggression against Gaza to put an end to rocket attacks against the Israeli towns.
The deadly Israeli onslaught has so far failed to stop Palestinian rocket attacks.
The Palestinian democratically-elected government of Hamas demands a cessation of an 18-month Israeli blockade on the Gaza Strip before its fighters suspend the rocket attacks.
The coastal strip has been under a tight Israeli blockade after the movement won an overwhelming victory in Palestinian parliamentary elections. The Israeli blockade forbids the entry of basic supplies including food, fuel, medicine, turning the Strip into an "open prison".