WASHINGTON - The Obama administration is taking a range of steps short of war to force Iran to take more seriously negotiations over its disputed nuclear program, in hopes of forestalling an Israeli attack, a US newspaper reported Monday.

These steps include planned naval exercises and new anti- missile systems in the Persian Gulf, and a more forceful clamping down on Iranian oil revenue, the New York Times reported in a front-page story.

President Barack Obama is also considering making warnings about what might bring about American military action against Tehran, as well as covert activities that have been previously considered and rejected, it said.

The US and over 25 other countries will hold the largest scale mine-sweeping exercise on September 16-27 in the Persian Gulf, in a show of unity and a defensive step to prevent Iran from attempting to block oil exports through the Strait of Hormuz.

The US is also racing to complete a new radar system in Qatar in the coming months that would combine with radars already in place in Israel and Turkey to form a broad arc of anti-missile coverage, the report said.

Washington is considering launching further cyber operation like the cyber attack code-named "Olympic Games" that infected Iran's nuclear centrifuges, in a bid to slow down the Iranian nuclear program.

Another proposal, advocated by some former top security officials, supports launching a "clandestine" military strike, just like the one launched by Israel against Syria's nuclear reactor in 2007, to destroy Iranian nuclear facilities.

But a covert strike against Iran is much riskier than the one targeting Syria, which did not respond to the Israeli attack, because Iran is militarily stronger and is certain to retaliate by striking Israeli and American targets in the Middle East.  

Due to the high political and military risks of attacking Iran that could have on his re-election, Obama has chosen to impose tough sanctions and other measures short of war to deter Tehran from crossing the "red line" of taking the final step to develop a nuclear weapon.

Washington also pins hope on the nuclear talks between Iran and six global powers, including the five UN Security Council permanent members and Germany, to resolve the Iranian nuclear crisis. However, the talks have failed to produce tangible progress after three rounds held this year in Istanbul of Turkey, Baghdad of Iraq and Moscow of Russia.

The US and its Western allies have imposed a series of crippling sanctions on Iran in order to prevent Iran from acquiring a nuclear weapon, though Tehran insists that its nuclear program is solely for peaceful energy purposes.

Israel, which regards Iran as the arch rival that threatens its existence, has been pressuring the US to take more resolute measures, including military attack, to force Tehran to abandon its nuclear ambitions.