JERUSALEM, July 7 -- Israel Defense Forces Chief of Staff Dan Halutz said on Friday that some 40 Palestinian militants had been killed since the army started a major ground operation in the Gaza Strip on June 28, Israel Radio reported.

A Palestinian man injured in an Israeli air attack is sent to a nearby hospital in northern Gaza Strip, July 7, 2006. Battles between Israeli troops and Palestinian militants in the northern Gaza Strip Thursday have killed at least one Israeli soldier and 15 Palestinians, according to sources from the Israel Defense Forces and a Palestinian hospital medics. [Xinhua/AFP]

"The terrorists have paid a heavy price so far," Halutz was quoted as saying.

But he underscored that Israel's blow to Palestinian militant cells in Gaza would not halt rocket attacks against Israel totally.

"It doesn't mean there won't be rocket fire if we leave tomorrow or the day after", he said, without disclosing when Israel planned to conclude the northern Gaza actions.

An Israeli soldier and about 20 Palestinians including civilians were killed on Thursday, the bloodiest single day in Gaza since Israel withdrew forces and settlers from it last summer after 38 years of occupation.

The Israeli army has expanded the operation in Gaza by entering into northern Gaza on Thursday in large numbers aimed to rescue an Israeli soldier abducted by Gazan militants on June 25 and stop the Palestinian rocket firing.