DHAKA: US President Barack Obama has welcomed Ukraine`s interim prime minister to the White House and pledged to "stand with Ukraine" in its dispute with Russia.

He warned Russian President Vladimir Putin the international community "will be forced to apply costs" if Russia does not remove its troops from Crimea, BBC reported.

Earlier, leaders of the G7 group of nations issued a similar threat.

Ukraine PM Arseniy Yatsenyuk, speaking after meeting Mr Obama, said Ukraine "will never surrender" to Russia.

"It is absolutely unacceptable to have Russian boots on the Ukrainian ground in the 21st century, violating all international deals and treaties," he said.

The diplomatic appeals to Moscow come ahead of Sunday`s referendum in Crimea, in which citizens will be asked if they want to stay with Ukraine or join Russia.

The Russian military and pro-Russian armed men moved in to seize key sites in Crimea - an autonomous region of Ukraine whose population is mainly ethnic Russian - in late February after the fall of President Viktor Yanukovych.

BDST: 1058 HRS, MAR 13, 2014