WASHINGTON - US President Barack Obama participated in the 2012 National Level Exercise on Tuesday, as an effort to examine the ability to respond to cyber threats affecting the country's critical infrastructure, the White House said, amid disputes over the reported cyberattacks on Iran authorized by the Obama administration.

As part of Tuesday's exercise sponsored by the Federal Emergency Management Agency, Obama hosted a Cabinet meeting to discuss with his team the time-sensitive decisions that would have to be made if a significant cyber event affected critical infrastructure systems, part of the agency's mandate to regularly test and evaluate the ability to respond to and recover from catastrophic events, said the White House Press Secretary Jay Carney in a statement.

An increase in reported cyber intrusions into US critical infrastructure networks shows that these systems are not being adequately protected, the statement said.

Obama noted in his State of the Union address earlier this year that the US Congress shall pass legislation to secure the nation from the growing danger of cyber threats.

However, some of Obama's Democratic allies and Republican rivals in the US Senate on Tuesday stepped into the ongoing disputes over a report by New York Times on US cyberattacks on Iran.

Obama ordered stepped-up cyberattacks on Iran's nuclear program months after taking office, significantly expanding America's first sustained use of cyberweapons, The New York Times reported last Friday. Senator Dianne Feinstein, the Democratic chairwoman of the Senate Intelligence Committee on Tuesday expressed worry that leaks to press about US cyber attacks on Iran authorized by the Obama administration could lead to a counter-attack on the United States.

She said the fact that the US is launching cyber attacks against other countries could "to some extent" provide justification for cyberattacks against the United States.

Republican Senator John McCain on Tuesday accused senior administration officials of leaking classified information to media to enhance Obama's image for his re-election bid but undermining US national security.

The program code-named Olympic Games and launched by the Bush administration, targets the computer systems that run Iran's main nuclear enrichment facilities, the New York Times reported.

However, a programming error allowed the worm, Stuxnet, which was developed by the United States and Israel, to escape Iran's Natanz plant and go around the world on the Internet in the summer of 2010.

Obama decided to press ahead with the program after seeing evidence that it was still causing havoc for the Iranians. In the following weeks, the Natanz plant was hit by a newer version of the computer worm, and then another after that.

In October 2010, Iranian Intelligence Minister Heidar Moslehi announced that Iran had detected and thwarted a virus aimed at infecting the country's nuclear plant system.

Iran said the computer worm, Stuxnet, had infected 30,000 IP addresses in Iran, including the personal computers of the staff at the country's first nuclear power plant, Bushehr.

Iran agreed to meet again in Moscow on June 18-19 with the six powers -- the United States, Britain, France, Russia, China and Germany, over its disputed nuclear program, following two rounds of talks respectively in April and in May.

Iran insists on the peaceful nature of its nuclear program, while the Western countries say it is a cover for developing nuclear weapons.