Fears Russia could try to swallow up its smaller neighbour Belarus by moving to create a greater political and economic union have intensified after a meeting between the country's leaders today.

Tensions between the two countries have been growing as Russian President Vladimir Putin's desire for further integrations continues.

Belarus' President Alexander Lukashenko is worried a new tax regime for oil planned for the new year could undermine his country's sovereignty.

The two leaders met in Moscow today where Putin laid out plans for a working group on further expansion of ties between Moscow and Minsk, the TASS news agency reported.

The key issue of the discussion for Belarus was the price of Russian natural gas and the issue of shortfall in revenue for Belarus due to Russia’s tax changes.

Russian President Vladimir Putin (right) and his Belarusian counterpart Alexander Lukashenko greeted each other with smiles during their meeting in the Kremlin in Moscow today

Russia was concerned about violations of the customs regulation between the countries and the illegal supplies of sanctioned goods.

The move could cost the Belorussian economy billions of dollars, economists have warned.

Putin and Lukashenko have met three times in a month to discuss the future relationship between the two nations.

Lukashenko has previously backed closure union with Russia, but suggested earlier this month that the Russian plan is designed to undermine his country's sovereignty and push Belarus towards Moscow by weakening its economy.

Putin told reporters today that both countries will work to expand plans for the 'construction of the Union State'.

He said: 'As has been agreed we are setting up a working group on further development of our ties in the economic area and other fields.

'In accordance with our proposal, we will work towards expansion of our plans regarding the construction of the Union State.

'I suggest that today we should discuss that issue, saying what has been done from our part.

'You said that you would give a respective instruction to the government so that the colleagues from the Belarusian side will contribute as well.'

President Lukashenko said previously he was worried plans for greater integration will 'destroy the country and become part of Russia'

Russia and Belarus have notionally been a 'union' state since 1997 but only of limited integration.

But wars in Georgia and Ukraine, as well as the annexation of Crimea, have made Belarus nervous about Russia's expansionist intentions.

Belarusian President Alexander Lukashenko said at a Russian press conference earlier this month: 'I can read between the lines and I understand the hints. You should just say it out loud: destroy the country and become part of Russia.'

Russian Prime Minister Dmitry Medvedev signed an order yesterday on creating a Russian-Belarus working group for discussion of various aspects of integration and controversial issues.

The pair held four hour-long rounds of talks, during which they discussed the issues of integration between both countries, co--operation over energy, as well as the changes in the Russian tax legislation and the way it influences the Belorussian economy.

Putin told reporters today that 'we will work towards expansion of our plans regarding the construction of the Union State'

Konstantin Kalachyov, head of the Political Expert Group and Kremlin adviser said some politicians in Russia do not consider Belarus to be a separate nation and want to 'integrate' their closest ally as they did with Crimea.

He told the Independent: 'The president is worried about what will come after Lukashenko and already there are big problems.

'The economic relationship is no longer satisfactory for Russia, and ever since Crimea, Moscow has sensed Minsk no longer has its back politically.'

Vladimir Putin greeted Lukashenko with a warm handshake when they met at the Kremlin in Moscow, today.

President Lukashenko visited Russia for the second time in December - just three days after the first - for talks.

Earlier this year Belarus turned down Russian requests for an air force base and closer military co-operation.

Since increasing economic sanctions Belarus has increasingly leaned to the West to diversify the country’s economy.