Tehran: Iran on Thursday cast doubt on the "seriousness and sincerity" of an international coalition the United States is building against the jihadist Islamic State.
"There are uncertainties about the so-called international coalition against (IS) that was announced after the NATO summit in Wales" last week, foreign ministry spokeswoman Marzieh Afkham said.
"Its seriousness and sincerity to tackle the root causes of terrorism is fundamentally questionable," she said in statements carried by official news agency IRNA.
Afkham`s remarks come hours after US President Barack Obama vowed Wednesday to launch a "relentless" war against IS jihadists in Syria and Iraq in order to "destroy" them.
Last week Iranian Foreign Minister Mohammad Javad Zarif accused the United States of not taking the threat from IS militants in Iraq and Syria seriously.
He also charged that US aid had previously helped the jihadists, alluding to support given by Washington to so-called moderate rebels fighting to topple the government of Syrian President Bashar al-Assad.
Iran has been Assad`s main ally since the revolt against his rule erupted in March 2011 and has also provided military advisers to the Shiite-led government in Iraq to help it battle the jihadists.
IS has captured large parts of northern Iraq and eastern Syria.
Afkham echoed Zarif, saying some countries, which she did not name, have been helping the jihadists.
"Some of the countries in this coalition are among the ones who provided financial and security support for terrorists in Iraq and Syria," she said.
"Others are hoping to bring about political change in Iraq and Syria in favour of their own interests."
Her comments came as US Secretary of State John Kerry arrived in the Saudi city of Jeddah for talks aimed at building a coalition, including with Arab states and Turkey, against the Islamic State.
Iran has repeatedly accused Gulf monarchies of financing the jihadists.