A cacophony of Washington voices is again attempting to ratchet up pressure on Iran over its “malign influence” in Iraq and its suspect nuclear activities. Although military options remain on hold, Bush administration officials have been briefing for the first time on possible targets inside the Islamic republic. A dossier purporting to contain new evidence of Iranian assistance to Iraqi Shia militias opposed to the US presence is expected to be published in the coming days. The dossier, ordered by the US commander, General David Petraeus, will detail recently discovered caches of rockets, mortars, roadside bombs and armour-piercing explosives that US says were supplied by Iran.

US officials claim increased rocket attacks on Baghdad’s Green Zone, including one during last week’s visit by the secretary of state, Condoleezza Rice, are a result of Iran’s accelerated efforts. The defence secretary, Robert Gates, said last week that “what Iranians are doing is killing American servicemen inside Iraq”. He also said Iran “is hell-bent on acquiring nuclear weapons”.

Much of the new information was gathered during recent joint US and Iraqi army operations in Basra. Other evidence was reportedly obtained from alleged Iranian agents detained in Iraq. In a series of briefings to the American media, administration officials claimed Tehran has reneged on last year’s agreement with Iraq’s PM, Nouri al-Maliki, to halt weapons supplies. Instead, they say Iran has continued to train, equip and arm militiamen at camps inside Iran.

Admiral Michael Mullen, chairman of the joint chiefs of staff, told a Pentagon press conference that no military action was currently being contemplated. But he said Iran, which was showing no sign of backing off, should not underestimate the depth of Washington’s concerns, or its determination to resolve them.

A third Middle East conflict involving US forces, in addition to Iraq and Afghanistan, would be “extremely stressful”, Mullen admitted. But in a clear indication of the form any future strikes might take, he went on: “I have reserve capability, particularly in our navy and our air force. So it would be a mistake to think we are out of combat capability.” Two unidentified senior administration officials told the New York Times last week that the feasibility of attacks, presumably launched by air from US bases and ships in the Gulf, had already been discussed. The targets were training camps, safe houses and weapons storehouses inside Iran, they said.

Some regional experts suggest Washington’s primary aim is to force Iran and Syria to back off in Iraq (and Lebanon and Palestine) and effectively isolate them, rather than to find an excuse to attack. Reducing Iranian influence is seen as crucial to winning broad Arab support for the Maliki government, something Rice worked on during a Gulf visit last week.

But there is no reason to believe that hardliners in Washington and Israel, unconvinced by November’s US national intelligence estimate, have stopped looking for an opportunity to halt Iran’s nuclear advance before Bush’s time runs out. Despite assurances by both sides that violence is not contemplated, naval incidents in the Gulf involving US and Iranian vessels in which shots have been fired — the latest happened last Thursday — are one potential trigger for more confrontations. — The Guardian