BAGHDAD – US officials are questioning Iraq about Iranian flights in Iraqi airspace suspected of ferrying weapons to Syrian President Bashar Al-Assad, whose conflict with rebels threatens to drag his neighbours into a regional struggle. Iraqi Prime Minister Nuri Al-Maliki's government is close to the regional Shi'ite power Iran, Assad's main ally, and he has opposed demands by Sunni Arab Gulf nations that Assad step down to end the escalating conflict over his rule. Three prominent US senators visiting Baghdad told Maliki that ties with Washington would be damaged if his government permitted Iran to use its airspace to deliver arms to Syria. One US official urged Baghdad to inspect the Iranian flights. “This could really have some impact on Iraqi-US relations if it were true. The fact of the matter is they have the right to order a plane to land if they think they may be violating their airspace," Sen. John McCain told Reuters. McCain said Maliki told the visiting lawmakers he had still not received evidence of arms supplies that Iraq requested when US officials raised the Iranian flights earlier this year. “If we make the allegation, I think is a legitimate request on his part to see the proof of it," McCain said. US State Department spokesman Patrick Ventrell said Wednesday Iraq had a responsibility to continue with measures to prevent Iran shipping arms through its airspace. – Reuters