Jerusalem ? At least 20 people were injured Sunday in an explosion in a market in the coastal city of Netanya that was apparently caused by a suicide bomber, rescue services said. Israel television said at least one person was killed.

Yeruham Mandel, another spokesman for the emergency services, said that five of the injured were in serious condition.

“There was an explosion, apparently a suicide bomber,” Mandel said.

There was no immediate claim of responsibility. Police could not confirm the reported fatality.

At least 20 people were injured in the blast, said Avi Zohar, a spokesman for Magen David Adom, Israel’s rescue service.

Israel radio said security forces were on alert in the area of Netanya in central Israel for several hours after information was received that a suicide bomber was preparing an attack.

Netanya, which is close to the West Bank, has been frequently targeted by Palestinian militants. In March, an attack in Netanya killed 29 people at a Passover seder, sparking Israel’s recently concluded five-week offensive in the West Bank aimed at dismantling the militant groups in the Palestinian autonomous zones.

“Anyone who thought that the Palestinian terror campaign against Israelis is over is completely mistaken,” said David Baker, an official at Prime Minister Ariel Sharon’s office. He spoke moments after news of the blast was broadcast on Israel radio. “The Palestinian terror campaign continues unabated, as does Israel’s battle against terror.”

Two weeks ago, Israel planned another offensive in Gaza after a suicide bombing in a Tel Aviv suburb that was claimed by the Gaza-based Hamas militant group – but that operation was postponed at the last minute as the international community urged restraint.