"I, the government and the parliament are ready to take the decision to introduce martial law in all territories of Ukraine," Poroshenko said at a government meeting. Under martial law, the highest-ranking military officer effectively temporarily takes over as the head of government should civilian authorities fail to function.

Martial law would, however, also affect foreign investment in Ukraine, including a key loan from the International Monetary Fund. Ukraine and the IMF have been in talks over a bailout that could grow to $40 billion.

Poroshenko also said Ukraine and the European Union would speak "with one voice" at peace talks in the Belarusian capital, Minsk, later on Wednesday, where they are hoping to negotiate a ceasefire between Ukrainian forces and pro-Russian separatists in eastern Ukraine.

Earlier on Wednesday, Russian President Vladimir Putin had confirmed he would travel to Minsk to take part in talks with Ukraine, Germany and France. "Russian President Vladimir Putin today is travelling to Minsk where he will participate" in the four-way talks, the Kremlin said in a statement.

Meanwhile Russian Foreign Minister Sergey Lavrov told reporters that there was "noticeable progress" made in talks held ahead of the negotiations at the highest level, which aim to find a way out of 10 months of fighting.

A spokesman for German Chancellor Angela Merkel said the meeting in Minsk offered a "glimmer of hope" but nothing more and that it was not clear "whether a result can be achieved."

While Ukraine is demanding control of its borders and the withdrawal of all foreign troops, Moscow has said it was "unrealistic" for Kyiv to regain control of its border under the current circumstances. The Kremlin has denied aiding the pro-Russian rebels, who are expected to argue that any peace accord reflect their recent territorial gains.

Meanwhile, fighting rages on in eastern Ukraine, with some 19 soldiers killed and 79 injured during the past 24 hours, according to the defense ministry in Kyiv. In Donetsk, the separatists said that six civilians were killed and eight injured when a rocket exploded at a bus station. On Tuesday, a rocket attack hit the city of Kramatorsk, where the Ukrainian military operation is headquartered.

ng/sms (AP, Reuters, dpa)