Ukraine's military has clashed with pro-Russian rebels in two eastern towns overnight, according to the Ukrainian interior and defence ministries, amid accusations by the US that Russia is going against "the spirit" of a deal to ease tensions.
Ukrainian soldiers retook control of the town hall in the southeastern port city of Mariupol on Thursday morning, and repelled an attack on an army base in the eastern town of Artemivsk, the ministries said.
Separatist sources also reported the loss of the town hall in Mariupol. The city was the scene of a rebel attack on troops last week that left three rebels dead. The separatists had held the town hall since April 13.
"The town hall is liberated and can function normally," Arsen Avakov, the interior minister, said on his Facebook page.
The Defence Ministry said in a statement that Ukranian forces repelled nearly 100 separatists who "opened fire with automatic weapons, machine guns and grenades" in an attack on the military base in Artemivsk, just north of rebel-held Donetsk.
"The attackers were repelled and suffered significant losses," Oleksandr Turchynov, Ukraine's acting president, said.
Avakov's Facebook message referred to a Russian with a "vast beard" leading the attack.
The AFP and Reuters news agencies meanwhile reported that a rebel-held checkpoint in Slovyansk had been commandeered by Ukrainian troops after rebels apparently abandoned the position.
The AFP further reported that rebels holding the town hall were ordered to leave by Ukraine troops.
The clashes were reported after the US president, Barack Obama, said Russia had failed to abide by the spirit of a deal to ease tensions in Ukraine, and that new sanctions against Moscow were being "teed up".
Obama said that "malicious armed men" continued to occupy buildings in eastern Ukraine, in contradiction to a deal agreed last week in Geneva by Ukraine, Russia, the EU and the US.
"So far we have seen them not abide by the spirit or the letter of the agreement in Geneva," Obama said. If that continued, he said, "there will be further consequences and we will ramp up further sanctions."
On Wednesday Sergey Lavrov, the Russian foreign minister, gave warning that Russia would respond if its interests were threatened, and made reference to Russia’s invasion of Georgia in 2008 after Georgian forces attacked separatists in its pro-Moscow region of South Ossetia.