Beirut :  Israel can probably live with the diplomatic cost of its bloody storming of Turkish-backed aid ships bound for Gaza — unless its US ally fails to shield it.

Israel's high-seas interception of the flotilla, in which nine people were killed, has provoked a firestorm of criticism around the world and shredded the Jewish state's already tattered relationship with Turkey, once its only Muslim ally.

Demands will intensify for Israel to end its siege of Gaza's 1.5 million Palestinians, decried as "inhumane" by Turkish Prime Minister Tayyip Erdogan yesterday. The European Union and Russia urged Israel to open crossings for aid, goods and people.

Another casualty, at least for now, is US President Barack Obama's effort to get indirect Israeli-Palestinian peace talks moving. Monday's drama will further test the credibility of Obama's broad drive to regain the trust of Arabs and Muslims. So far Obama has only voiced regret at the casualties and called for clarification of what happened in the raid. The UN Security Council condemned the "acts" that led to casualties and urged an investigation "conforming to international standards".

Israel has weathered world outrage over its policies towards Palestinians and its Arab neighbours often in the past, largely because it could rely on Washington to veto hostile resolutions at the UN Security Council and protect it from any punishment.

The flotilla assault may further harm Israeli Prime Minister Benjamin Netanyahu's rocky relationship with Obama, but the US leader is likely to think twice before joining global censure of Israel ahead of mid-term Congressional elections in November.

Unless, that is, he senses a new mood among Americans coming to view Israel as a liability, rather than an ally.