Putin, Obama still in dialogue: Kremlin

Russian President Vladimir Putin and his US counterpart Barack Obama have not stopped their contacts due to the situation in Ukraine, the Kremlin said Saturday.

"The conversation is continuing quite regularly. The previous conversation between the two presidents took place last week," Xinhua quoted Kremlin spokesman Dmitry Peskov as saying.

"There are a lot of disagreements now, and therefore these dialogues are sometimes very tough, but nevertheless, communication is continuing."

Russia's Federal Migration Service said Friday the country has introduced border control on the crossing points between its newly-adopted republic of Crimea and Ukraine.

Russian Foreign Minister Sergei Lavrov Friday accused the West of being only interested in the Ukrainian economy and not the welfare of its people.

Meanwhile, US Secretary of State John Kerry accused Russia of refusing to take "a single concrete step in the right direction" in the past seven days.

The leaders of the Group of Seven (G7) industrialised nations agreed Friday night to impose more sanctions on Russia over its "inaction" in easing the tension in eastern Ukraine.

Acting Ukrainian Prime Minister Arseny Yatsenyuk Friday accused Russia of violating the compromise Geneva agreement and urged the international community to unite their efforts to secure peace in the world.

The standoff between Russia and Ukraine peaked Thursday, when Russia began drills near the border with Ukraine in response to Kiev's "anti-terror" operation, which left five pro-Moscow protestors dead.