Two raids kill 15 Iran-backed fighters in Syria in 24 hours

Air strikes in eastern Syria killed nine Iran-backed fighters on Sunday, hours after a similar raid killed six others, the Britain-based Syrian Observatory for Human Rights said.

The opposition activist group said Israel was "likely responsible" for the strikes that targeted positions of Iran-backed forces near the Iraqi border.

The fighters killed in the early Sunday raids were mostly Iraqi nationals, observatory head Rami Abdurrahman said, according to AFP. Four Syrian nationals were among the six fighters killed in Saturday's attack.

There was no official comment from Israel, which rarely confirms details of its operations in Syria. Israel considers Iran's involvement in Syria a threat and says it will stop its attacks.

Since the start of the Syrian civil war in 2011, Israel has targeted government troops, allied Iranian forces and fighters from the Lebanese group Hezbollah.

On Saturday, air strikes, also attributed to Israel, hit positions belonging to government forces and Iran-backed militias near the border with Iraq, the observatory said.

On 23 June, suspected Israeli strikes killed seven fighters, including two Syrian soldiers strikes in the eastern province of Deir Ezzor and the southern province of Sweida, according to Syrian media.

The observatory said the increase in attacks has led to concerns among Iran-backed forces in east Syria that Israeli agents may be among their ranks.

These forces have arrested four people on suspicion of providing intelligence to Israel, the activist group reported on Sunday, shortly before the latest raids.

The attacks come as the US administration intensifies its sanctions campaign against the Syrian government and its Iranian allies 

Last week, the US Caesar Act, a law that targets businesses linked to the Damascus-led reconstruction efforts in Syria with crippling sanctions, went into effect.