"Another batch of 10 aircraft has been sent to the customer. China will receive the remaining 10 aircraft in 2018," the source said.
The Federal Service for Military-Technical Cooperation has declined to comment on the report.
Earlier, a source close to military and technical cooperation told TASS that the first four fighter jets had been delivered in late 2016. In November 2016, Vladimir Drozhzhov, deputy director of the Federal Service of Military-Technical Cooperation, told TASS Russia had started fulfilling the first phase of its contract with China.
Russia and China clinched a deal for 24 Su-35 fighter jets to the tune of at least $2 bln in November 2015. The contract also covers the ground equipment and spare engines.
The Su-35 is a Russian-made multipurpose generation 4++ super-maneuverable fighter jet equipped with a phased array radar and steerable thrusters. It can develop a speed of up to 2,500 kilometers per hour and has a flying range of 3,400 kilometers and a combat radius close to 1,600 kilometers. The fighter jet is armed with a 30mm gun and has 12 hardpoints for carrying bombs and missiles.