WASHINGTON, July 20 (AFP) - US concerns about Iran persist, but Washington is pained to define a diplomatic approach to a country it views as paid-up member of the "axis of evil," and no handy policy aspirin appears available to soothe the headache.
Relations have been stretched over nuclear weapon allegations and claims Tehran has aided terrorism, but Washington`s sudden presence in Iraq and Afghanistan -- both countries border Iran -- has sparked calls for an urgent diplomatic dialogue.
Exhibiting the decades-long festering mistrust, US President George W. Bush on Monday said Washington was probing the possibility that Tehran had offered assistance to some of the terrorists who conducted the September 11, 2001 attacks against the United States.
However, Bush asserted there was no definite proof yet that this had occurred, and he didn`t mention any possible consequences for Iran.
The US Department of State also declared Monday that its differences with Iran had not diminished, saying the country supported terrorism, pursued weapons of mass destruction and had an appalling human rights record.
State Department spokesman Richard Boucher, however, was also vague on what line should be taken with Iran, and said such a decision ultimately rests with Bush.
He said Washington would be willing to open a dialogue with Iran, "if and when the president determines it`s in our interest to do that."
Asked about Iran`s influence in Iraq, where like Iran a majority of the population are Shiite Muslims, Boucher hedged his bets.
"We`ve expressed concerns about what some Iranian groups were doing inside Iraq, but we`ve also said that at various moments, that they have been helpful," Boucher said.
On the nuclear question, Washington has criticised Iran for wanting to develop nuclear weapons, but appears to be leaving a judgement to the UN Security Council over possible sanctions.
Tehran has also been in Washington`s crosshairs over its support of various radical groups hostile to US ally Israel, and due to the presence of Al-Qaeda members on its soil.
Iran says it has neutralized Al-Qaeda`s presence, but Washington remains skeptical this has been fully accomplished.
The two countries broke off diplomatic relations in 1980 after US diplomats were taken hostage in the American embassy during the Islamic revolution that overthrew Iran`s monarchial government.
Washington is regularly derided as the Devil by the Iranian regime, while Bush lumped Iran in the axis of evil alongside North Korea and the former regime of Iraqi dicatator Saddam Hussein.
But the thorny question of relations with the oil-rich state that is three times the size of Iraq and has three times Iraq`s population persists.
Iran sits at a strategic crossroads in the Middle East, bridging Asia and the Caucasus.
A report prepared by the influencial and independent Council on Foreign Relations, counsels Washington to open a needed dialogue with Tehran as its government is unlikely to change soon.
"The lack of sustained engagement with Iran harms American interests, and direct dialogue with Tehran on specific areas of mutual concern should be pursued," the report urged.
"The urgency of the concerns surrounding [Iran`s] policies mandates the United States to deal with the current regime rather than wait for it to fall," it said.
"US reliance on comprehensive unilateral sanctions has not succeeded in its stated objective to alter Iranian conduct and has deprived Washington of greater leverage vis-a-vis the Iranian government apart from the threat of force," it found.
The study was overseen by Zbigniew Brzezinski, a former national security advisor to Jimmy Carter who was president during the Iranian revolution.