Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

The Syrian military has begun moving fighter aircraft and personnel back to Shayrat Airfield in Homs, Syria according to three U.S. defense officials.

Shayrat is the airfield that the U.S. hit with 59 Tomahawk missiles on April 6 in response to a chemical attack on civilians by the Assad regime earlier that week. The April 4 gas attack on the town of Khan Shaykhun was launched from the airbase.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

The Syrians have repaired some of the damaged infrastructure and just in the past few days began to move Su-22s and MiG-23s back to the airfield.

Related: U.S. Launches Missiles at Syrian Airbase After Gas Attack on Civilians

"They will be flying out of there again soon," one U.S. defense official said.

None of the officials could say whether the Syrian regime has more chemical weapons stockpiled at the base.

The U.S. intentionally avoided locations on the base where they suspected the Syrians could have chemicals stored during the Tomahawk strikes last month.

Could the Syrians use the base to launch attacks with chemical weapons again? "They could, but hopefully they learned their lesson last time," one official said.