An adviser to Ukrainian President Volodymyr Zelensky said on Saturday that Russia's attack on the capital Kyiv was not advancing and that around 3,500 Russian soldiers had been killed or injured so far in Moscow's assault on Ukraine.
Russian President Vladimir Putin launched what he called a special military operation before dawn on Thursday, ignoring Western warnings and saying the "neo-Nazis" ruling Ukraine threatened Russia's security, in the biggest attack on a European state since World War Two.
"We are striking the enemy around Kyiv. The enemy is not moving for now," said Oleksiy Arestovych.
Arestovych's comments were echoed by U.S. defense official who said Ukraine's forces were putting up "very determined resistance" to the three-pronged Russian advance that has sent hundreds of thousands of Ukrainians fleeing westwards, clogging major highways and railway lines.
Witnesses in Kyiv reported occasional blasts and gunfire in the city on Saturday evening, but it was not clear exactly where it was coming from. The capital and other cities have been pounded by Russian artillery and cruise missiles.
Zelensky also said Ukrainian forces were repelling Russian troops advancing on Kyiv "We have withstood and are successfully repelling enemy attacks. The fighting goes on," Zelensky said in a video message from the streets of Kyiv posted on his social media.
He also welcomed proposals by Turkey and Azerbaijan to hold peace talks with Russia, and singled out his conversation with Italy's Prime Minister Mario Draghi as key agreeing more international support to Ukraine.
"We will fight as long as it takes to liberate the country," Zelensky said in the short video, adding his country was currently lacking oil and oil products.
The crisis has galvanized the NATO Western military alliance, which has announced a series of moves to reinforce its eastern flank. While NATO has said it will not deploy troops to Ukraine, some western nations announced they were shipping more weapons to help the country's outgunned military.
U.S. President Joe Biden also approved the release of up to $350 million worth of weapons from U.S. stocks, while Germany, in a shift from its long-standing policy of not exporting weapons to war zones, said it would send anti-tank weapons and surface-to-air missiles.
In the meantime, the United Nations Security Council is due to vote on Sunday to call for a rare emergency special session of the 193-member U.N. General Assembly on Russia's invasion of Ukraine, which would be held on Monday, diplomats said.
The vote by the 15-member council is procedural so none of the five permanent council members - Russia, China, France, Britain and the United States - can wield their vetoes. The move needs nine votes in favor and is likely to pass, diplomats said.
Only 10 such emergency special sessions of the General Assembly have been convened since 1950.