US Vice President Joe Biden and Ukrainian Prime Minister Arseniy Yatsenyuk on Thursday expressed their concern about continued violence in eastern Ukraine, the White House said.

In a telephone talk, the leaders also voiced their concern regarding the refusal of fighters in eastern Ukraine to allow for unimpeded access for monitors to the territory they control, the White House said in a statement.

Clashes between government troops and pro-independence insurgents persisted in eastern Ukraine despite a ceasefire deal reached in the Belarusian capital of Minsk on Feb. 12. Both sides claim they observe the ceasefire, accusing each other of attempting to derail the truce.

Over the phone, Biden expressed condolences for the loss of life in a mine accident in eastern Ukraine, and regretted the refusal of rebels to allow Ukrainian rescue teams access to the site of the mine accident, said the statement.

Thirty-two miners were killed and another was missing in a methane gas explosion early Wednesday in eastern Ukraine's Donetsk region, authorities said Thursday.

In addition, Biden congratulated Yatsenyuk on the passage of crucial reform legislation that will help Ukraine return to economic health and pave the way for additional front-loaded financial support from the international community.