Syrian warplanes have reportedly taken off from the air base targeted by US air strikes, less than 24 hours after it was pounded by dozens of US cruise missiles.

Donald Trump ordered the strikes on the Shayrat base, near the city of Homs, in response to a chemical attack on the rebel-held town of Khan Sheikhoun earlier this week.

The Syrian government has been widely blamed for the attack, although it insists rebel groups were responsible.

The US Navy fired 59 cruise missiles at the base, killing at least seven people and causing what was described as extensive damage.

But within hours it was back in use according to the Syrian Observatory for Human Rights.

The London based monitoring group which uses sources on the ground to keep track of events in the country, said that Syrian army jets had taken off from the base to carry out strikes on rebel-held areas near Homs, .

They had "done the impossible" in order to continue using the base for sorties, the Observatory said.

The US air strikes triggered a major international row after they were angrily condemned by Russia.

In pictures: US missile strike against Syria Show all 7 1 /7 In pictures: US missile strike against Syria In pictures: US missile strike against Syria The guided-missile destroyer USS Porter (DDG 78) launches a tomahawk land attack missile in the Mediterranean Sea AP In pictures: US missile strike against Syria The United States military launched at least 50 tomahawk cruise missiles at al-Shayrat military airfield near Homs, Syria, in response to the Syrian military's alleged use of chemical weapons in an airstrike in a rebel held area in Idlib province EPA In pictures: US missile strike against Syria Shayrat airfield in Syria Getty Images In pictures: US missile strike against Syria US Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea Reuters In pictures: US missile strike against Syria US Navy guided-missile destroyer USS Ross (DDG 71) fires a tomahawk land attack missile in Mediterranean Sea Reuters In pictures: US missile strike against Syria President Donald Trump speaks at Mar-a-Lago in Palm Beach, Fla., after the US fired a barrage of cruise missiles into Syria in retaliation for this week's gruesome chemical weapons attack against civilians AP In pictures: US missile strike against Syria Syria's President Bashar al-Assad Reuters

Vladimir Putin’s government, which has consistently supported Syrian President Bashar al-Assad, said the strikes were a contravention of international law.

The US had carried out “an act of aggression against a sovereign state delivered in violation of international law under a far-fetched pretext", the Kremlin said.

Russian Prime Minister Dmitry Medvedev said the US had come “within an inch” of clashing with Russian forces.

Satellite imagery suggests the Shayrat base is home to Russian special forces and military helicopters.