A senior Israeli diplomat has given a positive view of Chuck Hagel's nomination as US defense secretary, though some commentators in the Jewish state expressed worries that the choice could open a new fissure in bedrock ties with Washington.

US President Barack Obama, a Democrat, named the former Republican senator for the Pentagon post on Monday, setting the stage for a confirmation battle with critics who question his commitment to Israel in its struggle with Iran and other regional adversaries.

But Israeli Deputy Foreign Minister Danny Ayalon, a former envoy to the United States, told the country's biggest-selling newspaper, Yedioth Ahronoth, in comments published on Tuesday: "I have met him (Hagel) many times, and he certainly regards Israel as a true and natural US ally."