US Vice President Joe Biden pressed Iraq Prime Minister Nuri al-Maliki in a telephone call Friday to bar the passage of weapons shipments to Syria through Iraqi airspace, the White House said.
"The vice president and the prime minister addressed issues of regional security, including the need to prevent any state from taking advantage of Iraq's territory or air space to send weapons to Syria," the statement said.
Earlier this month, the United States called on Iraq to make Iranian aircraft flying over Iraq land for inspections, after members of the US Congress raised fears the Iranian planes were ferrying weapons to the Syrian regime.
Senators John McCain, Lindsey Graham and Joe Lieberman raised their concerns with Maliki during a visit to Baghdad after the New York Times reported that Iran was once again using Iraqi air space to send arms to Syria.
"The easiest way, we think, is for them to require these aircraft to land and be inspected in Iraqi territory," said State Department spokesman Patrick Ventrell at the time, noting that Baghdad has had full control of its airspace since US troops withdrew in December.
In March, under US pressure, Iraq had warned Iran that it would not tolerate the passage of weapons destined for Syria through its territory or airspace.
President Barack Obama has delegated the task of managing the White House's dealings with Iraq to Biden, a former senator and chairman of the foreign relations committee.