The German Foreign Ministry has advised German citizens to leave the eastern and southern regions of Ukraine amid the escalation of the military conflict.

Earlier the ministry "insistently recommended" that Germans abstain from visiting eastern and southern Ukraine.

German diplomats described the situation in some Ukrainian regions as "extremely tense", the Deutsche Welle Radio said on Tuesday.

The Foreign Ministry mentioned, for instance, the occupation of administrative buildings by armed people in Donetsk and Luhansk.

"Tensions continue to escalate in these cities since the beginning of an anti-terrorist operation of Ukrainian security forces against pro-Russian separatists," the ministry said.

It also called attention to the Odesa disturbances, which claimed over 40 lives on May 2.