"We need advanced defence capabilities to inspect overflights" of Iraq territory, ambassador Lukman Faily said in a question-and-answer session on Twitter.
Baghdad is already "acquiring integrated air defence systems from the US. This has already passed congressional approval," he said.
On February 4, the Pentagon announced a $700 million agreement -- notified to Congress -- to sell Iraq an air traffic control radar system.
Washington suspected the aircraft of transporting weapons and fighters to the Syrian regime, which has received Tehran's support, amid a brutal, nearly-three-year civil war.
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Americans have been less vocal in recent months over this issue, but Faily said "a number of random inspections have taken place."
In addition, to help Iraq fight al-Qaeda and other Sunni extremist groups, such as the jihadist Islamic State of Iraq and the Levant (ISIL), Washington promised to speed up its delivery of Hellfire missiles and surveillance drones. The Pentagon is ready to sell more missiles and 24 Apache attack helicopters.
But he ruled out direct aid from Washington, in particular of drone strikes on insurgent camps: "we agree with Secretary Kerry that this is Iraq's fight," he Tweeted.
Since 2013, Iraq has seen a resurgence in violence approaching levels not seen since 2008. More than 1,000 people were killed in January alone, according to the government.
The attacks are especially concentrated in Baghdad, and in the majority-Sunni regions in the west and north of the country.
Diplomats and experts have repeatedly emphasised that the Sunni community's unhappiness with Shiite President Nuri al-Maliki has contributed to the increase of violence. But Maliki has decided to hold a firm line, with two months to go before legislative elections in April.