The EU and Russia today agreed to discuss their sharp differences over Ukraine and eastern Europe as President Vladimir Putin again warned against foreign meddling in former Soviet states.

Putin went into a summit with European Council President Herman Van Rompuy and European Commission head Jose Manuel Barroso billed as a "clear the air session" only for both sides to come out stressing the positives.

Apparently aiming to calm the waters in Ukraine, Putin also promised not to review crucial aid worth $15 billion even if the opposition, hostile to closer ties with Russia, takes power there.

"In direct answer to your question as to whether we will review our agreements on loans and energy if the opposition comes to power -- no we will not," Putin told a press conference after the talks.

"This is not important to us," Putin said, noting that Moscow had had "a very constructive dialogue" with Ukraine when it was led by now-jailed opposition leader Yulia Tymoshenko.

At the same time, "we want to be sure that this money comes back," the president added.

Putin's comments came against a backdrop of fast-moving events in Ukraine, where the government resigned and parliament repealed a raft of anti-protest laws which had sparked violent clashes in Kiev.

The Russian leader went into a summit lasting a little under three hours with Van Rompuy and Barroso which EU officials said was much needed to review strained ties.

In November, Moscow pressured Ukraine into dropping a trade and political deal meant to be the centrepiece of the EU's much vaunted Eastern Partnership strategy -- tightening relations with Armenia, Azerbaijan, Belarus, Georgia, Moldova and Ukraine on the basis of shared democratic values.

Only Georgia and Moldova remain on track after Ukraine ditched the accord.

There had to be some "straight talking," one EU official said, amid growing exasperation with Russian efforts to try to bring its former Soviet-era satellites in eastern Europe firmly back into its fold.