Syria's air defences have confronted a new "aggression", shooting down missiles over the central region of Homs, according to state-run media.
The reports did not say who carried out the pre-dawn strikes. The government-run Syrian Central Media said the missiles targeted the Shayrat air base in Homs.
Earlier this month, four Iranian military personnel were killed in an air strike on Syria's T4 air base, also in Homs.
Syria and its main allies Iran and Russia blamed Israel for that attack. Israel did not confirmed or deny mounting the raid.
The reports came just a few days after the United States, Britain and France conducted air strikes targeting alleged chemical weapons facilities in Syria, in retaliation for a suspected chemical weapons attack that they blamed on the Syrian government.
Experts from the international chemical weapons watchdog are now in Damascus and have been waiting to visit the site of the suspected chemical attack in the town of Douma, just east of Damascus.
On Monday, Syrian and Russian authorities prevented investigators from the Organisation for the Prohibition of Chemical Weapons (OPCW) from going to the scene, the head of the OPCW said, blocking international efforts to establish what happened and who was to blame.
The US and France say they have evidence that poison gas was used in the April 7 attack in Douma, killing at least 40 people, and that Syrian President Bashar Assad's military was behind it.
But they have made none of that evidence public, even after they, along with Britain, carried out air strikes on Saturday, bombing sites they said were linked to Syria's chemical weapons programme.
Syria and its ally Russia deny any chemical attack took place, and Russian officials went even further, accusing Britain of staging a "fake" chemical attack.
British Prime Minister Theresa May accused the two countries - whose forces now control the town east of Damascus - of trying to cover up evidence.
The lack of access to Douma has left unanswered questions about the attack.
OPCW Director-General Ahmet Uzumcu said Syrian and Russian officials cited "pending security issues" in keeping its inspectors from reaching Douma.
"The team has not yet deployed to Douma," Mr Uzumcu told an executive council meeting of the OPCW in The Hague on Monday.
Instead, Syrian authorities offered them 22 people to interview as witnesses, he said, adding that he hoped "all necessary arrangements will be made... to allow the team to deploy to Douma as soon as possible".
Russian military police were ready to help protect the OPCW experts on their visit to Douma, said Major General Yuri Yevtushenko of the Russian military's Reconciliation Centre in Syria.
Igor Kirillov, a Russian chemical weapons protection expert in The Hague, said the team is set to visit the site on Wednesday.
Earlier on Monday, Russian Deputy Foreign Minister Sergei Ryabkov said the inspectors could not go to the site because they needed approval from the UN Department for Safety and Security.
He denied that Russia was hampering the mission and suggested the approval was held up because of the Western air strikes.
"As far as I understand, what is hampering a speedy resolution of this problem is the consequences of the illegal, unlawful military action that Great Britain and other countries conducted on Saturday," he said.
However, UN spokesman Stephane Dujarric said the United Nations has "provided the necessary clearances for the OPCW team to go about its work in Douma. We have not denied the team any request for it to go to Douma."