Ukraine's Emergencies Ministry says the death total has reached 18 from Friday's explosion at a mine in the country's east.
President Viktor Yanukovych flew to the mine in Luhansk region to meet with families late Friday.
Yanukovych has called for a government commission to investigate the blast that initially killed 16, injured three others and left nine people missing.
News reports quote regional officials as saying they believe the blast was caused by methane.
Ukraine's coal mines are among the world's most dangerous, in part because of outdated equipment.
Some information for this report was provided by AFP and Reuters.