Satellite images released Friday of the Syrian air base that was pounded with 59 U.S. Tomahawk missiles show large-scale destruction to airfields, planes and fueling facilities allegedly used by the Assad regime to mount chemical weapons attacks.

However, the London-based Syrian Observatory for Human Rights reported that Syrian warplanes were able to take off from the base and carry out airstrikes in the countryside near Homs.

Shayrat air base was "almost completely destroyed" by the barrage of 1,000-pound warheads launched from the Eastern Mediterranean Sea early Friday, according to a human rights group in the country.

U.S. intelligence sources told Fox News they believe with "high confidence" that a deadly gas attack on Syrian civilians was carried out by government aircraft at Shayrat air base, southeast of Homs.

"Initial indications are that this strike has severely damaged or destroyed Syrian aircraft and support infrastructure and equipment at Shayrat Airfield." — Capt. Jeff Davis, a Pentagon spokesman

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The Britain-based Syrian Observatory for Human Rights said the missile attack damaged over a dozen hangars, a fuel depot and an air defense base.

At least seven Syrian soldiers were killed and nine wounded in the airstrike, the country's military said.

The governor of Homs province said he did not believe the strikes caused a large number of "human casualties." A Syrian official the attack caused deaths and a fire, but did not elaborate.

Two senior defense officials with knowledge of the strike also told Fox News that about 20 Syrian jets were destroyed.

None of the jets managed to take off and escape before U.S. missiles hit the target, the officials said, adding that all of the destroyed aircraft were jets -- not helicopters. No Russian aircraft were at the Sharyat airfield.

U.S. officials told Fox News there were between 12 and 100 Russian military personnel present at the base when the missiles hit and said the U.S. "took pains" to avoid hitting their barracks.

The U.S. missiles hit at 3:45 a.m. local time in Syria. Syrian state TV called the attack an "aggression" that lead to "losses."

"Initial indications are that this strike has severely damaged or destroyed Syrian aircraft and support infrastructure and equipment at Shayrat Airfield, reducing the Syrian government's ability to deliver chemical weapons," Captain Jeff Davis, a Pentagon spokesman, said, according to Reuters.

Davis said the U.S. was still assessing the result of the 59 Tomahawks it fired, expressing hope that Assad's government learned a lesson. He said it was ultimately "the regime's choice" if more U.S. military action would be needed.

Fox News is told the missiles were the Tomahawk “E” or Echo version. It is the latest model and has two-way satellite communication allowing the missile to be reprogrammed in flight if needed. The missiles can carry 1,000-pound warheads.

Syria's state TV showed footage of a fast sequence of orange flashes that lit the dark sky in the distance before the crack of dawn. The shaky footage was apparently filmed with a mobile phone camera and aired Friday.

In a different sequence after day break, the Syrian TV station al-Ikhbariyah showed another short clip of smoke billowing in the distance, hovering over a raging fire, the tip of which emerges and a forest of trees is in the foreground.

The U.S. launched the nearly five dozen cruise missiles in response to a chemical weapons attack that killed dozens of civilians, the first direct assault on the Damascus government since the beginning of that country's bloody civil war in 2011.

U.S. officials called the airstrike a "one-off" and said there are no plans for escalation.

Russia, meanwhile, condemended the attack, calling it an "aggression against a sovereign state" and a violation of international law.

Shortly before the strikes, the head of information policy commission in the upper house of Russian parliament, Alexei Pushkov, said on Twitter said that if President Trump launches a military action in Syria it would put him in "the same league with Bush and Obama."

Trump on Thursday called for all “civilized nations” to join the U.S. “in seeking to end this slaughter and bloodshed in Syria.”

Fox News' Jennifer Griffin and the Associated Press contributed to this report.