The State Department’s security bureau is back in the market for a contractor to fly surveillance drones over U.S. embassies abroad and along diplomats’ travel routes, according to contracting documents posted Monday.

The department relied on surveillance drones to aid security personnel at the U.S. embassy in Iraq through August 2012 and began seeking a contractor for drone support at other embassies in September 2011, according to contracting records. That proposed contract was for up to five years and $1 billion, the largest non-military drone procurement to date.

State canceled that solicitation in May, saying none of the competitors met its minimum requirements.

Monday’s sources sought notice restarts the contracting process but with reduced technical requirements and seemingly on a smaller scale. Unlike the earlier request for proposals, Monday’s notice is only directed at companies the government defines as small businesses rather than aerospace contracting giants such as Lockheed Martin and BAE Systems.

A sources sought notice doesn’t obligate the State Department to buy any new systems.

U.S. drones have been controversial in nations where the Defense Department and Central Intelligence Agency use them for surveillance and warfare such as Pakistan and Yemen. Civilian agencies have also used drones to collect data about things such as weather, pollution and crop yields.

The Diplomatic Security Service’s previous drone work has “proven valuable in static security, route reconnaissance, and movement over watch,” the sources sought notice said.

“The surveillance they offer over fixed installations provides for real-time assessment of potential threats,” the notice continued. “The availability of [unmanned aerial vehicle] systems allows reconnaissance of proposed movement routes, identification of alternate routes, and threat evaluations prior to convoy departure. The surveillance they provide significantly improves situational awareness.”

The diplomatic security bureau has been investing heavily in new technology the past several months in an effort to thwart attacks such as the assault on a consulate in Benghazi, Libya, that killed Ambassador Christopher Stevens and three other Americans.

The bureau also has invested in new training in recent months and put more than $1 billion toward embassy construction projects focused on improving security.

The proposed drone system would be completely owned and operated by contractors, the notice said, and the contractor must be able to field drones at embassies worldwide.

The drones should be capable of flying up to 12 hours each day and 10 hours on average days while continuously collecting video, the notice said. They should also be able to send back high quality still images while in flight.

The system should be able to operate at night and when GPS navigation is unavailable, the notice said.

The department’s Iraq drone program was run primarily by KUK Construction, a subsidiary of the Anchorage-based Alaska native corporation Olgoonik Development, according to contracting records. The contract was valued at about $7.5 million.