During a surprise visit to Baghdad on Sunday (March 24), U.S. Secretary of State John Kerry urged Iraqi Prime Minister Nuri al-Maliki to stop Iranian flights over Iraq from carrying arms to Syria.

A U.S. official said earlier on condition of anonymity that Washington believes flights and overland transfers from Iran to Syria via Iraq take place nearly every day, helping Syrian President Bashar al-Assad crush a two-year-old revolt against his rule.

Kerry said he had "a very spirited discussion" with Maliki about the issue and he made clear U.S. unhappiness about the suspected arms transfers on Iranian flights through Iraqi airspace.

"I made it very clear that for those of us who are engaged in an effort to see President Assad step down and to see a democratic process take hold with a transitional government according to the Geneva communiqué, for those of us engaged in that effort anything that supports President Assad is problematic. And I made it very clear to the prime minister that the over flights from Iran are in fact helping to sustain President Assad and his regime," Kerry said at a press briefing at the U.S. Embassy in Baghdad.

Iraqi officials have denied allowing weapons to be flown from Iran to Syria through Iraqi airspace.

At his news conference, Kerry said the United States had "agreed to try to provide more information" to the Iraqis and suggested that sentiment in the U.S. Congress may be turning against Iraq because of the suspected arms transfers to Assad.

Iraq's Shi'ite-led government says it takes no sides in Syria's conflict, but its interests are closely aligned with those of neighbouring Shi'ite Iran, a strong supporter of Assad.

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