Germany's foreign minister warned that Ukraine is "close to war" after Ukrainian officials released reports Tuesday that at least 30 pro-Russia separatists have died in clashes in East Ukraine.

German Foreign Minister Frank-Walter Steinmeier gave the warning in interviews that were published in European newspapers on Tuesday, USA Today reports.

Steinmeier referenced the clashes in Odessa, in which 46 people died Friday after a pro-Ukraine march led to fighting between pro-Russians and pro-Ukrainians. A fire erupted in a building during the fighting, which killed the people trapped inside the burning building.

"The bloody pictures from Odessa have shown us that we are just a few steps away from a military confrontation," Steinmeier told El País, Le Monde, Gazeta Wyborcza and La Republica.

He also said that the clashes have reached a violent point of contention "that a short time ago we would not have considered possible."

On Tuesday, Ukraine's Interior Minister Arsen Avakov said that the deaths of the pro-Russia separatists occurred in violent clashes near Slavyansk, a town in East Ukraine that has many pro-Russia rebels.

"We estimate that the terrorists lost more than 30 people," Avakov wrote in a post on Facebook. He added that four pro-Ukraine troops died in the fighting, which also left more than 20 more injured.

Ukraine's government in Kiev said that pro-Russia rebels used heavy weaponry against Ukraine's units in the "anti-terror" operation.

Ukrainian forces have been trying to quell pro-Russia rebels in the east since early last week, and have infiltrated the city of Slovyansk.

Russia said that it will add more warships and submarines to its Black Sea naval fleet, according to the Interfax news agency.

Authorities in Kiev also announced that they were firing the acting governor of the Russian-speaking Odessa region and will replace him with Ihor Palytsya, a member of Ukrainian parliament.

Odessa's police chief was fired on Saturday, as Kiev is now concerned that Odessa could be next region to succumb to pro-Russia forces, especially after 67 pro-Russia separatists were released Friday under pressure from other pro-Russia separatists.

The Ukraine government also sent an elite national guard to Odessa to patrol the city.