The New York Times reports: The United States has increased its manned and unmanned surveillance flights over Iraq since ISIS swept across the north of the country, and is now flying about 30 to 35 missions a day. The American flights include F-18s and P-3 surveillance planes, as well as drones.

Iran has mounted a parallel effort, according to American officials. It has set up a special control center at Al Rashid airfield in Baghdad, and is flying its own small fleet of Ababil surveillance drones over Iraq, said one American official.

An Iranian signals intelligence unit has been deployed at the same airfield to intercept electronic communications between ISIS fighters and commanders, said a second American official, who also declined to be named because he was discussing classified information.

While Iran has not sent large numbers of troops into Iraq, as many as 10 divisions of Iranian military and Quds Force troops are massed on the border, ready to come to Mr. Maliki’s aid if the Iraqi capital is imperiled or Shiite shrines in cities like Samarra are seriously threatened, American officials say.

“Iran is likely to be playing somewhat of an overarching command role within the central Iraqi military apparatus, with an emphasis on maintaining cohesiveness in Baghdad and the Shia south and managing the reconstitution of Shia militias,” said Charles Lister, a visiting fellow at the Brookings Doha Center in Qatar.