Explosions and artillery fire outside the eastern Ukrainian cities of Mariupol and Donetsk threatened to shatter a day-old cease-fire between Kyiv and pro-Russia rebels less than two days after it was imposed.
Heavy explosions struck overnight on September 6-7 on Mariupol's eastern outskirts, where Ukrainian troops retain defensive lines against the rebels.
The volunteer, pro-Kyiv Azov Battalion said on Facebook that its positions were hit by Grad rockets but did not give details.
The BBC reported early on September 7 that both sides were firing artillery at each other. It also was reporting that Mariupol had been surrounded by Russian-backed separatists.
But a spokesman for the Ukrainian National Security and Defense Council announced that the "situation in the city is under control."
Later in the day, an RFE/RL correspondent there described Mariupol as "calm and stable," with fewer people on the streets but shops seemingly open as usual.
He noted that there was "enhanced patrolling" and National Guard troops were present downtown.
Mariupol is a port city of about half a million people on the coast of the Sea of Azov, and lies on a major highway that runs from the southeast of the country to Odesa.
Rebels recently opened a new front on the coast, leading to fears that the separatists were trying to secure a land corridor between Russia and the Crimean Peninsula, which Russia annexed in March.
Steady shelling was heard near Donetsk in eastern Ukraine early on September 7, with plumes of black smoke raising fears that cease-fire was on the verge of collapse.
The shelling came from an area near Donetsk airport, which has been controlled by Ukrainian government forces but attacked regularly since May by Russian-backed separatists.
Western Weapons, Advisers?
Meanwhile, a senior aide to Ukrainian President Petro Poroshenko said on September 7 that Kyiv had reached agreement during the NATO summit in Wales on the provision of weapons and military advisers from five member states of the alliance.
Yuriy Lytsenko said under a "New Start" heading on his Facebook page, "At the NATO summit agreements were reached on the provision of military advisers and supplies of modern armaments from the United States, France, Italy, Poland, and Norway."
He gave no further details and there was no immediate confirmation of his statement.
The presidents of Ukraine and Russia said on September 6 that the cease-fire was mostly holding, but the truce still appeared fragile as both sides of the conflict claimed violations.
Ukrainian President Petro Poroshenko said he and Russian President Vladimir Putin discussed steps "for giving the cease-fire a stable character" in a telephone conversation on September 6.
The Kremlin said both leaders expressed satisfaction "with the fact that the sides of the conflict were overall observing the cease-fire regime."
Colonel Andriy Lysenko, a spokesman for Ukraine's national security council, said rebels had fired at Ukrainian forces on 10 occasions after the cease-fire took effect.
A top rebel leader, Aleksandr Zakharchenko, claimed government forces had violated the cease-fire early with two rounds of shelling in the town of Amvrosiivka, about 50 kilometers southeast of Donetsk.
"At this time the cease-fire agreement is not being fully observed," he said. He didn't say when the supposed breach occurred.
Lysenko said Ukrainian forces were strictly observing the cease-fire and suggested that Zakharchenko's claim was a provocation.
Based on reporting by RFE/RL's Ukrainian Service, Reuters, AFP, AP, and BBC