Israel shelled Syrian fighters after gunfire from the Syrian civil war spilled over to the Israel-controlled Golan Heights, the military said today, as the conflict appeared to inch closer to the Jewish state.

The civil war in Syria has renewed tensions in the Golan Heights, a strategic plateau that Israel captured from Syria in the 1967 war. Despite constant hostility between the two countries, Syria has been careful to keep the border quiet since the 1973 Mideast war.

In recent days Israeli troops have fired into Syria twice, responding to what appeared to be stray mortar shells exploding in Israel-held territory.

Today, an Israeli military spokesman said soldiers fired artillery toward the source of gunfire late last night.

He said the military identified a hit. He did not know whether the targets were Syrian rebels fighting to topple President Bashar Assad or forces loyal to him.

Syrian shells have exploded inside the Israel-held Golan Heights several times in recent weeks, damaging apple orchards, sparking fires and spreading alarm but causing no injuries.

Though the two nations have been bitter enemies, Israel is concerned that if the Assad regime is toppled, Syria could fall into the hands of Islamic extremists.

Meanwhile, French foreign minister Laurent Fabius has said Israel and Hamas are both to blame for the violent clashes in Gaza.

"There are rockets being fired from Gaza and Israel has the right to defend itself, but at the same time there are these deadly Israeli attacks on Gaza," Fabius said today in an interview with France2 television from Tel Aviv. "That's why we need an immediate cease-fire."

Mr Fabius is in the region to meet Israeli and Palestinian Authority leaders, and has also spoken with US secretary of state Hillary Clinton.

Fresh clashes erupted in the West Bank today as Palestinian youths threw rocks at Israeli soldiers, who responded with tear gas.

Anger in the West Bank over what is happening in Gaza has not only been directed at Israel: many also blame the Palestinian Authority for failing to take action over the Gaza offensive and for co-operating with the Israeli security forces against protesters.

Hazem Abu Helal was arrested after joining a protest at the Bet El checkpoint near Ramallah after several female demonstrators were arrested by the Israeli army. “They began shooting a lot of tear gas so I moved back to the City Inn Hotel, which is inside the Palestinian controlled area,” he said.

Abu Helal was detained not by the Israeli army but by Palestinian security forces, who took him to a Ramallah police station for questioning. “They said, ‘You’re making a problem for the [Palestinian Authority]’,” Abu Helal said. “They told me, ‘Go make a demonstration in Ramallah’.”

According to Shawan Jabarin, the director of Al-Haq, a Palestinian human rights group, Palestinian security forces often suppress protests against Israel in the West Bank. “They stop them, arrest them, beat them sometimes,” Mr Jabarin said.

On Sunday, he said, Palestinian security forces prevented protesters from reaching Israel’s Al Jalame checkpoint near Jenin. “The Palestinian police have become a guard for Israel’s interests,” he said.

President Mahmoud Abbas has not been to Gaza since bloody clashes saw his western-backed Fatah movement kicked out of the strip five years ago. Since then the division between the Fatah-dominated Palestinian Authority, which controls the West Bank, and Hamas, which rules Gaza, has created divergent economic, social and political realities.

These differences are being compounded by the war in the Gaza Strip.

Abbas and other West Bank leaders have condemned the Gaza operation, but their lack of action on this latest violence, said Dr Samir Awad, a professor of political science at Birzeit University near Ramallah, is not enough for most Palestinians.

“The Palestinians in the West Bank are not happy to sit here, where they are separated from Gaza,” Dr Awad said. “The Palestinian Authority did not do anything to stop security co-ordination with Israel or even threaten the future of peace talks during this attack on Gaza.”

Agencies/Guardian service