Lyon -- The imam's sermon during Friday prayers at the Lyon mosque was unmistakably conciliatory, but it did little to cool the anger of some French Muslims over Israel's Gaza offensive.

Thousands of faithful crowded the mosque in the central French city -- men in the main prayer room and women on the first floor -- as the death toll from Israel's deadliest conflict in the Palestinian territory hit 1,100.

"I'm tired of sobbing in front of my television set, thinking about all these women, children and men from Gaza being killed by bombs," said a man after prayers.

The day's sermon delivered in Arabic and translated into French aptly tackled "the many trials that God imposes on man," providing a segue for the imam to touch on the delicate topic of Arab-Jewish relations in France.

"Our feelings towards our Palestinian brothers must not allow us to forget that our relationship with Jews and Christians is one of friendship," he said.

The war between Israel and the Palestinians is "a political conflict, not a religious conflict, not a conflict between Jews and Muslims," the imam argued.

Afterwards, outside the mosque, two men unfurled a white sheet to take up a collection "for the Palestinian brothers and sisters" and the coins and bills came raining down.

Last week, the congregation managed to collect almost 19,000 euros (25,000 dollars) and the mosque has invited French Muslim families to sponsor Palestinians who have lost their homes in the bombings.

Home to Europe's biggest Muslim and Jewish populations, France has been on edge since Israel began its offensive in the Gaza Strip three weeks ago, sparking a surge in anti-Semitic attacks.

A Jewish man was stabbed four times in a Paris suburb late Thursday in an apparent anti-Semitic attack, three synagogues have been fire-bombed and vandals have daubed anti-Israeli graffiti on other Jewish sites.

French politicians and religious leaders have issued several appeals for calm but the attacks have continued and a top Jewish group warned Friday that action was needed to avoid irreparable harm to community relations.

At the Lyon mosque, rector Kamal Kabtane made a point of meeting with local Jewish leaders this week to promote good inter-faith relations.

"It all went just fine," said Kabtane of the meeting.

"It is absolutely out of the question for the Middle East conflict to be transposed here, in France," he added.

But his views are challenged by the young men who attended Friday prayers, including 20-year-old Moktar who said he was disgusted with the war.

"I have marched in peaceful protests for the Palestinians, but what's the use? The war is getting worse day by day," he said.

Another worshipper complained the war pits David against Goliath, with Palestinian civilians paying the price. "It's like using a gun against someone who is unarmed," he said.

"If this continues, the war will have to spread to Israel's backers in America, or here," warned another.

Jerome Daquin/AFP/Expatica