MOSCOW: President Vladimir Putin on Monday eased restrictions on Russian companies working on Iranian enrichment sites as he travelled to Tehran for his first visit since 2007.

A decree Putin signed on Monday enables Russian firms to help modify centrifuges at the Fordo enrichment site and help Tehran redesign its Arak heavy water reactor.

Russian companies can now also carry out activities linked to Iranian exports of enriched uranium of more than 300 kilograms in exchange for the supplies of natural uranium to Iran, the Russian decree said.

Under a historic July deal with world powers, Iran agreed to dramatically scale back its nuclear programme, making it much more difficult for it to develop nuclear weapons.

Tehran agreed to slash by two-thirds the number of centrifuges, machines that can “enrich” or purify uranium to make it suitable for peaceful uses but also for a nuclear weapon.

Russian companies are eyeing business opportunities after sanctions on Iran are lifted, expected in the next two months, as the nuclear deal reaches its “implementation” stage.

Putin arrived in Tehran on Monday for talks with supreme leader Ayatollah Ali Khamenei and President Hassan Rouhani, with the Syrian conflict expected to be high on the agenda.

The one-day visit will also see Putin take part in a summit of gas exporting countries.

Russian jets hit 472 targets in Syria

Moscow on Monday said its warplanes had hit 472 targets in Syria in the past two days, including tanker trucks and oil infrastructure in territory controlled by the militant Islamic State (IS) group.

“In 141 combat sorties in the past two days, warplanes of the Russian Air Force struck 472 terrorist targets in the provinces of Aleppo, Damascus, Idlib, Latakia, Hama, Homs, Raqa and Deir Ezzor,” the Russian defence ministry said in a statement.

The military said that the latest strikes had destroyed 80 tanker trucks near the IS stronghold of Raqqa, as well as a large oil storage tank and a oil refinery south of the city.

Fuel reserves some 50 kilometres north of Deir Ezzor were also destroyed in the strikes, the defence ministry said.

The Russian defence ministry said last week that it was “hunting” oil transporters in a bid to cut IS financing and claimed that in the past five days some 1,000 fuel trucks had been destroyed.

The Russian military said that “terrorists” had suffered “serious losses” in Saraqib, a city in the northwestern province of Idlib province, and in the town of Qalaat al-Madiq in the Hama province.

President Vladimir Putin last week ordered the intensification of Moscow's bombing campaign in Syria after confirming that the Russian passenger plane that crashed in Egypt's Sinai last month, killing all 224 people on board, had been brought down by a bomb.

Assad said in an interview published Sunday that government troops were advancing on “nearly every front” thanks to the Russian air strikes, with Syrian state media reporting the regime had taken control over Maheen and Hawareen in the southeast of Homs province.