The United States is intensifying its push to build an international campaign against Islamic State jihadist fighters in Iraq and Syria, including recruiting partners for potential joint military action, Obama administration officials said on Wednesday.
Britain and Australia are potential candidates, US officials said. Germany said on Wednesday it was in talks with the United States and other international partners about possible military action against Islamic State but made clear it would not participate.
"We are working with our partners and asking how they might be able to contribute. There are a range of ways to contribute: humanitarian, military, intelligence, diplomatic," State Department spokeswoman Jen Psaki told reporters.
It's unclear how many nations will sign up. Some such as trusted ally Britain harbor bitter memories of joining the US led "coalition of the willing" in the 2003 invasion of Iraq that included troops from 38 nations. Others such as France refused to join the action. The claims of the existence of weapons of mass destruction which spurred the coalition to act were found to be false.
The United States, the officials said, could act alone if necessary against the militants, who have seized a third each of Iraq and Syria, declared open war against the West and want to establish a hub of jihadism in the heart of the Arab world.
Senior White House aides met this week to discuss a strategy for expanding its assault on Islamic State, including the possibility of air strikes on the militants' stronghold in eastern Syria - an escalation that would almost certainly be riskier than the current US campaign in Iraq.
While Iraq's government welcomed the role of US warplanes to attack the militants, Syrian President Bashar al-Assad has warned that any strikes conducted without his country's permission would be considered an act of aggression, potentially plunging any US led coalition into a broader conflict with Syria.
The government of British Prime Minister David Cameron said it has not received a US request for air strikes.
"This is not something under discussion at the moment," a government spokeswoman said. "Our focus remains on supporting the Iraq government and Kurdish forces so that they can counter the threat posed by ISIL, for example with the visit of our security envoy to Iraq this week and the provision of supplies to Kurdish forces."
A spokesman for Australian Prime Minister Tony Abbott said humanitarian aid in Iraq could continue but declined to say whether Australia would join U.S.-led military action.
"Our response to any request from the United States, or other close allies and partners, will be based on whether there is an achievable overall humanitarian purpose and a clear and proportionate role for Australia as well as on a careful assessment of the risks," Abbott's spokesman said.
US officials hope the relative success of humanitarian aid and recent strikes on militant weapons in Iraq will diminish allied fears over supporting new military action.
"There's been a proof of concept in Iraq that with a limited campaign you can do (things) against these guys," one official said on condition of anonymity. "What we did already (has yielded) 25 to 30 nations offering to help," the official added, referring to widespread international humanitarian aid.