President Barack Obama has been assailed for urging Israel to make concessions to the Palestinians, with detractors ranging from Republican presidential candidates to Democratic former mayors charging that Obama has failed to support and defend Israel.

But Obama has also secretly augmented military aid to Israel, including the sale of 55 powerful bombs known as bunker busters, Newsweek reported in a story to appear in Monday's magazine. Israel was initially denied its request for the bombs by President George W. Bush, but Obama signed off on the deal in 2009, shortly after taking office.

The bombs could be particularly useful in a military strike against Iran -- and former vice chairman of the Joint Chiefs of Staff James Cartwright told Newsweek that the administration has signed off on the sales despite a worry that it constituted a green light for Israel to attack Iran's secret nuclear sites one day. Obama has never precluded the possibility of a U.S. military strike on Iran, repeatedly saying that all options are on the table.

Obama: 'Rachet Up Cooperation With Israel'

Newsweek also cites Rep. Steve Rothman, D-N.J., who serves on the committees that fund both the U.S. military and foreign aid, as saying that Obama gave orders to the military to ratchet up the cooperation at every level with Israel.

Obama has also presided over American and Israel expanding their military cooperation through joint exercises, sent Israel $2.77 billion in security assistance funding in 2010 -- a record amount -- and immediately intervened when Egyptian protestors stormed the Israeli embassy, trapping six Israeli diplomats inside.

The President of the United States, Barack Obama ... used all of the considerable means and influence of the United States to help us, Israeli Prime Minister Benjamin Netanyahu said after the Egyptian embassy debacle. We owe him a special measure of gratitude.