Russia is ready to face a new round of Western sanctions over Ukraine, Prime Minister Dmitry Medvedev said Tuesday.

"I am sure we will be able to minimize their consequences," he said in a televised speech to parliament.

Russia on Tuesday banned the leader of Crimea's pro-Kiev Tatar community from entering the Black Sea peninsula for five years, the Tatar assembly said.

Mustafa Dzhemilev was handed an official order barring him from returning to Crimea as he crossed to mainland Ukraine from the territory that Moscow controversially annexed last month, the assembly said in a statement.

U.S. Vice President Joe Biden on Tuesday accused Russia of "trying to pull Ukraine apart" and pledged Washington's strong support for Kiev's leaders, as a Cold War-style confrontation over the former Soviet republic ratcheted up.

Biden was speaking in Kiev amid worrying signs on the ground that diplomacy was failing to calm the crisis.

New laws passed on Monday in Russia make it easier for native speakers and those who can prove they or their families have lived within the borders of the former Russian empire or Soviet Union to get citizenship.

The amendments were signed into law by President Vladimir Putin, who annexed the Russian-speaking peninsula of Crimea in Ukraine last month and has asserted his right to protect Russian speakers across the former Soviet bloc.

Russian President Vladimir Putin said on Monday he had signed a decree rehabilitating Crimea's Tatars, an ethnic group accused of collaborating with Nazi Germany and exiled under Stalin.

"I have signed a decree to rehabilitate the Crimean Tatar population of Crimea, the Armenian population, Germans, Greeks, all those who suffered during Stalin's purges," Putin told a government meeting.

Vice President Joe Biden started a two-day visit to Kiev on Monday in a pointed show of U.S. backing as Russia accused Ukraine's government of "grossly breaching" a deal designed to de-escalate separatist tensions.

Biden was to reinforce a message to Russia -- which Washington sees as supporting Ukraine's insurgency -- that time is running out for it to persuade pro-Kremlin rebels holding a string of eastern towns to comply with the pact struck in Geneva on Thursday, a senior U.S. official told reporters travelling with the vice president.

Five years after refashioning U.S. foreign policy to emphasize Asia, President Barack Obama will face questions over his strategy's content and staying power in the region this week.

Obama will counter the impression that events, including carnage in Syria and the East-West showdown over Ukraine have dragged his administration’s attention elsewhere.

Ukrainian Prime Minister Arseniy Yatsenyuk warned in an interview that aired Sunday that Russia is undermining global stability and nuclear nonproliferation efforts amid an ongoing crisis between Kiev and the Kremlin.

Ahead of a visit by U.S. Vice President Joe Biden, he also called for financial and economic support and help modernizing Ukraine's military -- while stopping short of asking for weapons.

Pope Francis celebrated Easter mass on Sunday with a message of social solidarity as the world's Orthodox marked a holiday marred by bitter divisions over Ukraine and clashes broke out in Jerusalem.

Francis led the ceremony for the holiest day in the Christian calendar on St Peter's Square, which will be followed by a special blessing and address to crowds of Catholic faithful in the famous Vatican piazza.

Pro-Kremlin rebels in east Ukraine appealed Sunday for Russian "peacekeepers" to sweep in after a deadly gunfight killed at least two of their militants, shattering an Easter truce and sparking "outrage" in Moscow.

But the Western-backed authorities in Kiev claimed the violence was a set-up by Russia to create a pretext for it to send troops in.