Kiev

German Chancellor Angela Merkel and French President Francois Hollande warned new sanctions might be approved against Moscow if May 25's Ukrainian presidential poll fails.

Russian President Vladimir Putin's trip to the recently-annexed Crimean peninsula was condemned by EU, US and NATO officials. 

At least seven people have died in Friday's clashes Ukraine's port city of Mariupol, according to local officials.

The injured were 39, according to the healthcare department at Donetsk's administration.

Latest data comes amid conflicting reports on the incident in the south Ukrainian city.

Bulgaria and Romania could send fighters after Russia's Deputy PM Rogozin while he was traveling to Transnistria via Bulgarian airspace, as he wrote on Twitter.

Dmitry Rogozin said he had been informed by the pilot that Bulgaria's air-control personnel had asked whether the "blacklisted passenger" was on board.

Gun battles between pro-Russian separatists and Ukrainian security forces took place in the port town of Mariupol in Ukraine, report local media. 

According to them the separatists attacked the Interior Ministry building in the town, but were repelled by the special battalion “Azov” and local security forces. Eight separatists were reportedly killed. 

Ukraine's Energy Ministry does not recognize the USD 3.5 B sum which Russian concern Gazprom says Naftogaz owes for gas supplies.

Yury Prodan, the Ukrainian Energy Minister, was quoted by RBC Ukraine as saying that Kiev will calculate its debt only under "market prices".

Donetsk to hold referendum on May 11

DONETSK -- The self-proclaimed People's Republic of Donetsk will go ahead and hold a referendum on independence as planned, on Sunday, May 11.

This decision was made on Thursday, despite Vladimir Putin's appeal to postpone the plebiscite.

Ukraine's government has announced it is ready to engage in talks with parties and regional representatives in the east, where unrest has been ongoing for weeks.

Kiev "won't talk to terrorists in east"

ki -- Ukraine's government is ready to talk to political parties and regional officials in the east on resolving the crisis, but not to "terrorists", Kiev announced.

Troops sent by Kiev as part of an "anti-terrorist" operation in eastern Ukraine have made progress retaking seized buildings in the port of Mariupol.

Wednesday's developments follow the entering of 10 army tanks and armored vehicles into Mariupol, which was revealed by witnesses cited by local media.