JERUSALEM, July 30 (Reuters/JMCC) - A rocket fired by Palestinian resistance fighters in the Gaza Strip struck the Israeli city of Ashkelon on Friday, causing damage but no casualties, officials said.

The attack was one of the first to strike the southern city after months of quiet since Israel launched a three week military campaign in the Hamas-ruled Gaza Strip in late 2008, called operation Cast Lead in Israel.

It was likely to elicit a military response from Israel.

No doubt this is the most serious event that happened since operation Cast Lead, Ashkelon mayor Benny Vaknin told Israel Radio. The city is located about 12 km (7 miles) up the coast from the Gaza Strip and has some 125,000 residents.

While rocket fire has continued since the devastating war, much of it has targeted smaller towns closer to the border.

Israel often carries out strikes against smuggling tunnels or outposts of the Islamist group Hamas after such attacks.

A police spokesman said the rocket was fired from the Gaza Strip and landed in a residential area.

No group in Gaza claimed responsibility for the rocket fire. Hamas has said it is trying to stop militants from firing at Israel, but smaller groups have continued the attacks. (Writing by Ari Rabinovitch; Editing by Alison Williams)