EU leaders have talked up the prospects of a breakthrough with President Vladimir Putin over Ukraine amid a divisive debate over whether to ease or lift European sanctions on Russia.

In a flurry of diplomatic activity German and Ukrainian leaders met in Berlin and the Latvian foreign minister headed to Kiev and Moscow. Momentum gathered behind a proposed summit in Kazakhstan next week between the Russian, Ukrainian and French presidents and the German chancellor.

Speaking in Riga, where this week Latvia assumed the six-month rotating EU presidency, Federica Mogherini, the EU’s foreign policy coordinator, spoke of “limited but positive” signals from the Russians in recent weeks over the conflict in eastern Ukraine and raised the possibility of lifting EU sanctions “partially or fully”. “The situation on the ground is slightly better than some months ago,” she said. “ There seems to be a different Russian attitude … I hope this is part of a new time, a new era.”

Putin’s actions on Ukraine have triggered the worst post-communist crisis in relations between Russia and the west over the past year. But, as well as muting his hardline policies on Ukraine recently, Putin was proving more cooperative on other sore points such as Syria and nuclear issues, she said.

Latvia, which along with the two other Baltic states has led the EU’s hawks on relations with Moscow, also talked up the chances of a breakthrough. There is a growing sense in EU capitals and in Moscow that Putin is looking for a way to save face on eastern Ukraine where Russia supports rebel separatists because the collapse of the oil price and the rouble, and the impact of sanctions are causing great distress to the Russian economy.

“We have a feeling they really want a lowering of sanctions,” said Edgars Rinkēvičs, the Latvian foreign minister. “This is an opening we can use.”

He will travel to Kiev on Friday and to Moscow on Sunday to explore the usefulness of staging a summit in Astana, the Kazakhstan capital, next Thursday. While the Latvian prime minister, Laimdota Straujuma, said the German and French leaders would negotiate with Putin soon, Mogherini said the Astana summit was not yet confirmed. Chancellor Angela Merkel of Germany, Putin’s key interlocutor, said she would decide in the coming days whether to take part.

The French and the Germans are at odds over whether to ease sanctions on Moscow, while the Americans are likely to take a dim view of relaxing the pressure on Putin.

The EU has to decide between March and July whether to renew sanctions on Russia imposed because of Russia’s annexation of Ukraine’s Crimean peninsula and its fomenting of rebellion against Kiev in eastern Ukraine.

“If there is no change in Russian behaviour and they [EU] don’t continue the sanctions, that would be absolutely extraordinary. We don’t want to contemplate that,” said a senior US official.

But argument is raging within the EU over the efficacy of sanctions, over their impact on Russia’s imploding economy and on European business. The Czechs, Slovaks, Hungarians, and Austrians are fierce opponents of sanctions, while Berlin and Paris are increasingly on opposing sides. President François Hollande of France spoke this week of the need for sanctions to be stopped, while Merkel stressed on Thursday that they have to be continued, subject to Russian behaviour.

“The key for us is a united EU position,” Rinkēvičs told the Guardian. “It’s difficult. Countries have very different approaches.”

After meeting Putin for four hours in Australia in November, Merkel voiced exasperation with the Russian leader. It is thought she will only go to Kazakhstan if confident of what she deems to be a positive outcome.