Clashes have caused some casualties , a statement from the mayor 's office says . Authorities advise residents to stay in their homes as violence erupts . - The government has declared three days of national mourning for those killed and injured during protests on Friday. Intense fighting broke out in eastern Ukraine on Monday when government air and ground forces attacked pro-Russian separatist gunmen who had seized an airport terminal . In response , Ukrainian air and ground forces attacked the airport .
Clashes have caused some casualties , a statement from the mayor 's office says . Authorities advise residents to stay in their homes as violence erupts . - The government has declared three days of national mourning for those killed and injured during protests on Friday. In response , Ukrainian air and ground forces attacked the airport .