Austrian Chancellor Sebastian Kurz said his country, which will take over the 28-nation EU's rotating presidency for six months in July, stands by EU sanctions but "will work to improve relations between the European Union and Russia."

"In particular, we hope that there will be progress in eastern Ukraine, so that sanctions can be removed step by step in accordance with the Minsk agreement," Kurz said, referring to a 2015 peace accord brokered by Germany and France that, so far, is far from fully implemented.

He added that "a win-win situation is better for both sides than a lose-lose situation."

Unlike many other EU countries, Austria didn't expel Russian diplomats over the nerve agent poisoning in Britain earlier this year of former Russian spy Sergei Skripal and his daughter.

Putin met in Vienna with liberal President Alexander Van der Bellen, the conservative Kurz and officials including Vice Chancellor Heinz-Christian Strache, whose nationalist Freedom Party entered the government in December as the junior coalition partner.

Over the weekend, Strache - whose party in 2016 signed a cooperation agreement with the main Kremlin party, United Russia - said it was time to lift sanctions against Russia.

Putin's sixth official visit to traditionally neutral Austria marks the 50th anniversary of the start of Soviet gas deliveries to the country.

After Tuesday's talks, the managers of Russia's state-controlled gas giant Gazprom and Austria's OMV signed an agreement on Russian natural gas supplies through 2040, a deal Putin said highlights the two nations' "significant contribution to energy security in Europe."

OMV is also among European companies involved in the planned Nord Stream 2 pipeline that would double the amount of gas Russia can send directly to Germany, skirting transit countries such as Ukraine - a project opposed by the US and some other EU members.

In Warsaw on Tuesday, Poland's president expressed his country's disapproval of the planned Russian-German gas pipeline to the visiting German president. Polish President Andrzej Duda said at a joint news conference with Frank-Walter Steinmeier that he believes Nord Stream 2 would undermine the security of central and eastern Europe.

The pipeline project has become a deeply divisive issue in Europe.

After meeting Putin in Vienna, Van der Bellen said some US politicians claim that the EU is too dependent on Russian gas, but overlook the fact that American liquefied gas is much more expensive.

"Under such circumstances, it makes little sense - viewed from a purely economic point of view - to replace Russian gas with American liquefied gas," he told reporters.

Putin, meanwhile, welcomed Austria's intention to provide humanitarian assistance to Syria.

He said that "if Europe wants to see the flow of migrants from Syria ... ebb, it's necessary to help people return to their homes and normalise life in their country."

AP