Israel has confirmed that reserve units have been sent to the Gaza Strip, as its campaign there enters a 17th day.
But military officials denied this heralded a new phase in Israel's offensive against Hamas militants.
Earlier, Prime Minister Ehud Olmert said Israel was nearing its military goals and operations would continue.
Reports suggest diplomatic efforts between Egypt and Hamas in Cairo are progressing, as envoy Tony Blair heads to the city for talks on Monday.
Nearly 900 Gazans have been killed during conflict, Palestinian medics say. Israel says 13 Israelis have died.
Nearly 40 people were killed across Gaza on Sunday, Palestinian sources said - 17 in Gaza City, as Israel's troops reportedly engaged in fierce fighting there.
Israel is preventing international journalists from entering the coastal strip, making it impossible to independently confirm such figures.