The Syrian regime has said one of its airbases had been bombed but it was unclear who had carried out the air strikes.

Syrian state TV reported loud explosions were near the T-4 airfield in the desert east of the city of Homs in the early hours of Monday. It said the airfield was targeted with several missiles and that Syrian air defence was responding, and had shot down eight incoming missiles. State TV said the attack was “most likely” American, a claim the Pentagon has denied.

Video footage on social media in Lebanon showed aircraft or missiles flying low over the country, apparently heading east towards Syria. The Sana state-run news agency said the strikes resulted in a number of “dead and wounded”.

Donald Trump had warned the regime and its backers that they would pay a “high price” for the use of chemical weapons on a rebel-held suburb of Damascus which killed 42 people. However, the Pentagon denied US forces were involved in the air strikes.

“At this time, the department of defence is not conducting air strikes in Syria,” a Pentagon spokesman said. “However, we continue to closely watch the situation and support the ongoing diplomatic efforts to hold those who use chemical weapons, in Syria and otherwise, accountable.”

Separately, the White House put out an account of a telephone conversation between Trump and Emmanuel Macron, in which the US and French presidents “agreed to exchange information on the nature of the attacks and coordinate a strong, joint response”.

Macron has said chemical weapons attacks in Syria would cross a “red line” for France, and French forces would strike if the regime was proven to have been involved.

There was also speculation that Israel could be behind the attack. It launched airstrikes against the T-4 base in February, claiming that an Iranian drone launched from the airfield had flown into Israel. When asked about the explosions, an Israeli spokeswoman declined to comment.

T-4, also known as Tiyas, halfway between Homs and the ancient ruins of Palmyra, has been used by the Russian air force, but it is unclear whether Russian aircraft were at the base when it came under attack.

The attacks come on the eve of a planned UN security council meeting to discuss the chemical weapons attack on the Damascus surburb of Douma, which affected at least 300 people, killing 42. Many of the dead had had been sheltering in the basement of a building that was struck by a projectile shortly after 7.30pm. Ill-equipped local doctors said they treated patients for suffocation, foaming at the mouth, dilated pupils and burned eyes.