US President Barack Obama opened his deepest foray into the Middle East quagmire, telling Israeli Prime Minister Benjamin Netanyahu he must stop Jewish settlements.

The leader should also grasp the "historic opportunity" to make peace with the Palestinians, Mr Obama said.

Both leaders are relatively new in their jobs, and they spoke of warm ties and extraordinary progress.

Mr Obama's readiness to speak out on settlements and stalled Israel-Palestinian talks, however, indicated he and Mr Netanyahu had not reached an agreement on the best way forward after intense talks.

Mr Obama also notified Iran it had until the end of the year to get serious about talks with the world community on curbing Tehran's nuclear ambitions.

The former Bush administration diplomatically bludgeoned Iran over its perceived nuclear weapons ambitions but refused to engage the Islamic government in Tehran.