Shayrat Airfield in Homs, Syria is seen in this DigitalGlobe satellite image released by the U.S. Defense Department on April 6, 2017 after announcing U.S. forces conducted a cruise missile strike against the Syrian Air Force airfield.

A Syrian air base targeted in a U.S. cruise missile attack is operating again, the governor of Syria's Homs province confirmed on Saturday.

The United States launched the missile strikes on Friday in response to a chemical attack that killed 90 people including 30 children. It says the Syrian government launched the attack from the Shayrat air base. Damascus has strongly denied carrying out the attack and says it does not use chemical weapons.

The Syrian army said on Friday the attack had caused extensive damage to the base, which the United States says it targeted with 59 Tomahawk cruise missiles.

"The airport is operating as a first phase," Homs governor Talal Barazi told Reuters. "Planes have taken off from it," he added, without saying when.

Asked if it was true that Syrian planes were now taking off from Shayrat or that the air base is operating, a Pentagon spokesman referred questions to the Syrian government.

The Syrian Observatory for Human Rights, a UK-based organisation that reports on the war, said warplanes had taken off from the base on Friday and carried out air strikes on rebel-held areas in the eastern Homs countryside.

An activist with an opposition air raid warning service said however that the first flight from the base was on Saturday morning.

U.S. President Donald Trump suggested on Twitter that the runway itself had not been the target of the missile strikes.