The Uncle Sam is ratcheting up efforts for a new UN sanction against Iran over its controversial nuclear plan while cranking up pressure on the Arabic countries to isolate Iran.

However, Iraqi issue is more intractable for the U.S. compared with Iran's alleged nuclear ambition, especially after a U.S. intelligence report said the Islamic Republic has halted its nuclear weapon project.

While accusing Iran of aiding Shiite militants in attacking the coalition troops and destabilizing Iraq's security, the U.S. is cognizant of the significance of winning Iran's cooperation in keeping Iraq's stability.

However, Ahmadinejad's visit to Iraq is far from a signal of cooperation with the U.S. but more likely to be a challenge, some analysts believed.

Even an expectation of a perfunctory cooperation between Iran and America is extravagant, as both are coveting the regional supremacy.

Ali al-Haj, an Iraqi political analyst, said that the visit by Ahmadinejad represents a challenge to America's influence in Iraq rather than a cooperation on the ground.

"Ahmadinejad is telling the Americans that I am here in Iraq and those Shiite Iraqis you bring to govern the country are actually realizing the significance of Iran's regional role more than you do," he said.

Ahmadinejad's visit serves Iran's interests

Surely, Ahmadinejad's high-profile visit to Iraq will not come only as a challenge to the U.S. influence in Iraq but must serve Iran's interests in multi-way.

Firstly, Iraq and the U.S. is eyeing to finalize an agreement by this summer, laying out future relationship between the two countries, including military ties.

It is deemed that Ahmadinejad timed his visit deliberately to assuage the impact of the envisaged U.S.-Iraqi strategic pact.

"I believe the timing has something to do with the talks over long-term strategic agreement between Iraq and America," Ibrahim al-Amiri, a politics professor with the Baghdad University, asserted.