Palestinians in the Gaza Strip fired three rockets at southern Israel late Wednesday, police said, raising the likelihood of an Israeli military response.

A police statement said there were no immediate reports of casualties and the location of the rockets' landfall had yet to be confirmed.

"A short time ago three rockets were fired in the direction of (the southern city of) Ashkelon," the statement said.

"Sites of impact have not yet been located."

Last Tuesday night a single rocket fell east of the port city of Ashdod and was followed a few hours later by four Israeli air strikes on Islamic Jihad targets in the Gaza Strip.

Nobody was hurt on either side.

Israeli public radio said the latest volley could be related to internal Gaza infighting between the strip's Hamas rulers and its extremist opponents.

There was no immediate claim of responsibility.

Hamas security forces on Tuesday shot dead a Salafist leader in Gaza City Tuesday during a confrontation.

The incident came as Hamas stepped up measures against militants belonging to Islamic extremist groups, some of whom are known as Salafists.

Since last summer, when Israel and Hamas fought a deadly 50-day war in and around Gaza, there have been growing signs of internal unrest between Hamas security forces and extremist splinter groups.

Salafists are Sunni Muslims who promote a strict lifestyle based on that of early "pious ancestors". In Gaza they have made no secret of their disdain for Hamas over its observance of a tacit ceasefire with Israel and its failure to implement Islamic law.