Russia said on Tuesday it hoped that talks on the status of eastern Ukraine would start shortly between Kiev and pro-Moscow rebels.

"We are hoping that the talks will start quickly," Russian foreign minister Sergei Lavrov told reporters, also urging Ukraine to conduct constitutional reforms.

The Russian defence ministry said on Tuesday that its planes had not approached a Canadian frigate on a NATO mission in the Black Sea in an incident Ottawa denounced as "unnecessarily provocative".

Russia's arrest of an Estonian policeman has sparked fears that Moscow is using the incident to test NATO's resolve to defend its small Baltic allies as the crisis in eastern Ukraine rumbles on.

The European Union agreed to a new wave of sanctions against Russia on Monday, but said their entry into force would take a few days, giving time to recent peace moves by Russia.

"Depending on the situation on the ground, the EU stands ready to review the agreed sanctions in whole or in part," said Herman Van Rompuy, President of the European Council after a last-minute meeting of EU envoys in Brussels.

Progressive Socialist Party leader MP Walid Jumblat on Monday stressed the importance of setting up a new regional system, “which includes Turkey and Iran,” to replace the Arab League and fight terrorism, calling against excluding Russia from any solutions in Syria.

“The Arab world will not be able to confront this challenge alone, and it's about time we reconsidered the concept of the Arab League and worked on establishing a new regional system, through expanding the league to include Turkey and the Islamic Republic of Iran,” said Jumblat in his weekly article in the PSP-affiliated al-Anbaa newspaper.

Ukrainian President Petro Poroshenko visited a flashpoint eastern city Monday where sporadic fighting has rattled a three-day-old ceasefire between government and rebel forces.

The highly-symbolic trip to the strategic port of Mariupol came just as EU officials called a new meeting to decide on fresh sanctions against Moscow should the truce fail.

Clad in the blue and yellow of Ukraine's national flag, Irina Dovgan stood on a street of the rebel-held city of Donetsk as passers-by punched, kicked and spat on her, sometimes crushing tomatoes in her bruised face.

Fighting around two flashpoint cities in eastern Ukraine on Sunday rattled a tenuous truce between government troops and pro-Russian rebels less than 48 hours after it came into force.

Insurgent militias bombarded a government-held checkpoint on the eastern edge of the port city of Mariupol overnight, local officials said, killing one woman and triggering panic among residents.

U.S. Secretary of Defense Chuck Hagel pledged on Sunday to boost military ties with Georgia amid the unfolding crisis in Ukraine.

"Our shared goal is to build even stronger military ties in the future, particularly in the light of Russia's blatant aggression in Ukraine," Hagel told a press conference in Tbilisi.

Amnesty International accused rival fighters in the Ukraine conflict of war crimes including indiscriminate shelling, abductions, torture, and killings, in a report compiled ahead of the ceasefire deal.