The U.S. government on Friday voiced concerns over the Iranian cargo flights which may be transferring arms into Syria through Iraq's airspace.

"Without getting into intelligence matters, we are concerned about the over-flight of Iraq by Iranian cargo flights headed to Syria," said U.S. State Department spokeswoman Victoria Nuland at a briefing.

Her remarks came after report said that the United States has requested the Iraqi government to stop allowing Iran to use its airspace or inspect the Iranian planes overflying its territories for suspicion that Tehran is flying weapons into Syria.

"We are consulting with Iraq about them. And we are making the point that any export of arms or related materials from Iran, frankly, to any destination would be a violation of U.N. Security Council Resolution 1747," said Nuland, referring to the UN resolution that bans arms export from Iran.

"The point that we're making to Iraq is to ensure that it is not aiding and abetting in any way a violation of U.N. Security Council Resolution 1747, nor that it is helping to arm the Syrian regime, given the positions that Iraq itself has supported in the Arab League," she added.

An Arab League summit is scheduled to be held in Baghdad, capital of Iraq, on March 29.