US Secretary of State John Kerry has said that Egypt has a key role to play in the battle against the Islamic State group in Iraq and Syria.

Kerry met with Egyptian President Abdel Fattah el-Sisi and Foreign Minister Sameh Shoukry in Cairo on Saturday on the latest leg of a regional tour to forge a coalition to battle the armed group.

"It will be our goal ... to degrade and ultimately to defeat [IS] wherever it exists," Kerry said.

The United States says it is "comfortable" it can build an international coalition to fight the Islamic State group, but with Western and Middle Eastern allies hesitant on the specifics, it risks finding itself out on a limb.

President Barack Obama this week unveiled a rough plan to combat Islamic State group fighters simultaneously in Iraq and Syria, thrusting the US directly into two different wars in which nearly every country in the region has a stake.

The broad concept of a coalition has been accepted in Western capitals and on Thursday 10 Arab states, including regional rivals Saudi Arabia and Qatar, signed up to a "co-ordinated military campaign".

"I'm comfortable that this will be a broad-based coalition with Arab nations, European nations, the United States, others," Kerry said in the Turkish capital Ankara on Friday.

But he added it was "premature" to set out what tasks individual coalition partners would shoulder.

Iran ruled out

US officials have said the coalition will be broad. However, when asked on Friday, Kerry ruled out Iranian involvement as inappropriate due to its support for the regime of Syria's Bashar al-Assad.

He said there were "any number of reasons" why Iran should not join a Paris conference on Monday to discuss coalition strategy.

Iran has never offered to join the coalition against Islamic State in Syria, describing it as "shrouded in serious ambiguities". It has sent soldiers to Iraq at the request of the Iraqi government to combat Islamic State fighters there.

"No one has called me and asked me with respect to the presence of Iran, but I think under the circumstances, at this moment in time, it would not be right for any number of reasons. It would not be appropriate, given the many other issues that are on the table with respect to their engagement in Syria and elsewhere," Kerry said.

The US on Friday said that it was at war with Islamic State, a day after Obama's statement that strikes against the group were to extend into Syria.

The comments by Pentagon and White House officials on Friday came as the US president was pressed to clear up doubts about how he saw the conflict with the group, also known as ISIL.

"The United States is at war with ISIL in the same way that we are at war with al-Qaeda," Josh Earnest, a spokesman for the White House, said.
(Al Jazeera)