Russia is to supply weapons to Iraq to help the country in its struggle against militant group Islamic State (Isis), Foreign Minister Sergei Lavrov said.

Speaking ahead of talks in Moscow between Russian President Vladimir Putin and Iraqi Prime Minister Haidar al-Abadi, Lavrov pledged Russian support in Baghdad's battle against the militant group, which only days earlier seized the strategically vital city of Ramadi, about 70 miles west of the capital.

The victory was a significant setback in Iraq's fight against Isis, in which they have been backed by air strikes from a US led coalition.

"We understand that the threat of terrorism is enveloping not just Iraq but the neighbouring countries," Abadi told reporters at a meeting with Russian Prime Minister Dmitry Medvedev, reports AFP.

"It evolves and takes new shapes, and we understand perfectly well that it requires heightened attention from Russia. We expect more active cooperation in this direction," Abadi said.

On the 70th anniversary of the Soviet Union's victory in World War II, he compared Iraq's struggle to Russia's against Nazi Germany.

"In a joint effort, we will be able to have victory over these new forces, similar to those that you overcame in the past," he told Medvedev.

Abadi last month visited Washington DC, as part of a tour to gain international support in the battle against Isis, who this week have also seized the ancient city Palmyra in Syria, leading to questions about the effectiveness of the West's anti-Isis strategy.

Russia is a key ally of Syria's President Bashar al-Assad, whose forces are battling Isis in Syria. In 2014, Russia supplied Iraq with Mi-28 attack helicopters, and in March Assad said that Russia had been supplying the country with weapons since 2011, contradicting Moscow's claims.

"We are glad to support and advance cooperation with Iraq at the government level," said Medvedev.