Top diplomats seek Ukraine solution in Paris talks
Russian Foreign Minister Sergei Lavrov has held talks with counterparts from the US and key EU states to try to resolve the crisis in Ukraine.
After the talks Mr Lavrov said it was agreed to continue discussions in the coming days but admitted that everyone was "concerned" at events.
US Secretary of State John Kerry said the talks were "tough" but that there were some concrete ideas to work on.
The EU earlier offered 11bn euros ($15bn; £9bn) of aid to Ukraine.
European Commission President Jose Manuel Barroso said the package of loans and grants over the next couple of years was "designed to assist a committed, inclusive and reforms-oriented government" in Kiev.
Ukraine's finance ministry has predicted it needs $35bn to rescue the economy.
The EU also froze the assets of 18 Ukrainians, accused of involvement in a deadly crackdown on protesters.
In other developments:
- Hundreds of pro-Russian demonstrators have stormed the regional government building in Donetsk for the second time in recent days
- Gunmen in Crimea threatened the UN secretary-general's envoy, Robert Serry, but he is reported safe
- Russian forces have seized two Ukrainian missile-defence sites in Crimea, according to unconfirmed reports
- Russian President Vladimir Putin and German Chancellor Angela Merkel discuss crisis in telephone call
Mr Lavrov met Mr Kerry and counterparts from the UK, Germany and France on the sidelines of a long-planned conference on Lebanon in Paris.
The Russian minister said it was agreed that all sides needed to respect an EU-brokered peace deal signed last month.
The US state department, however, denied any agreement had been reached.
The 21 February deal granted major concessions to the opposition, but pro-Russian President Viktor Yanukovych fled before it could be implemented.
"We had a long day of discussions on Ukraine," Mr Lavrov said.
"We are all concerned at what is happening there. We agreed to continue those discussions in the days to come... and that's it."
Mr Kerry said he had some concrete ideas to take back to President Barack Obama, adding: "I'd rather be where we are today than where we were yesterday."
Nato and Russia held parallel talks in Brussels.
Afterwards, Nato Secretary-General Anders Fogh Rasmussen said the organisation was reviewing all cooperation with Russia and was stepping up its engagement with the government in Kiev.
The US and Russia had appeared far from compromise in the lead-up to the Paris talks.
The US wants independent observers in the flashpoint region of Crimea and direct talks between Kiev and Moscow.
Russia was expected to call for greater representation for Ukraine's Russian-speaking areas in the Kiev government.
In the US, Pentagon chief Chuck Hagel announced plans to expand US military co-operation with Poland and Baltic states.
He said the US would step up joint aviation training with Poland, and increase its participation in Nato's mission to police the air space of Baltic countries.
The announcement was a direct response to concerns raised last week by Poland, he said.
Meanwhile, a recording of a phone conversation between EU foreign policy chief Catherine Ashton and Estonian Foreign Minister Urmas Paet has been leaked on the internet.
In the recording, Mr Paet told Baroness Ashton that there was an "increasing understanding" in Ukraine that ousted President Viktor Yanukovych's government was not responsible for the deaths of police and protesters during clashes last month in Kiev.
He said some Ukrainians believed elements from within the new regime in Kiev had employed snipers.
He said Ukrainian doctor Olga Bogomolets had told him that victims from both sides were shot by snipers using the same weapons.
However, Dr Bogomolets told the UK's Telegraph newspaper that she had never had access to victims from the government side and was unable to comment on how they had been killed.
Mr Paet confirmed that the conversation with Baroness Ashton had taken place on 26 February.
In a news conference on Wednesday, he called for an inquiry into the deaths in Kiev, but warned against using his comments to discredit the new government.
"I call for journalists to treat this recording very carefully. I was talking about the theories there were about what happened in Ukraine," he said.
Mr Yanukovych fled Ukraine shortly after the bloodshed and is now in Russia.
Moscow has since flooded the Crimea region with military personnel, claiming that Mr Yanukovych had asked for their help.
The Organisation for Security and Co-operation in Europe (OSCE) says it has sent 35 unarmed military monitors to Ukraine in response to a request from Kiev.