German Minister for Foreign Affairs Frank-Walter Steinmeier was shocked by the death of many people in Friday’s fire in Ukraine's city of Odessa.

"Tragedy of Odessa must be understood as a wake-up call!" he wrote on his Tweeter page, as cited by Voice of Russia.

The US State Department has published an official statement, saying “The United States today mourns with all Ukrainians the heartbreaking loss of life in Odessa. Today the international community must stand together in support of the Ukrainian people as they cope with this tragedy.”

“The violence and mayhem that led to so many senseless deaths and injuries is unacceptable. We call on all sides to work together to restore calm and law and order, and we call on the Ukrainian authorities to launch a full investigation and to bring all those responsible to justice... We again call for the immediate implementation of the commitments made in Geneva on April 17. The United States stands ready to support this implementation,” the statement said.

According to the latest reports, at least 46 people died in clashes between pro-Russian activists and Maidan supporters in Odessa on Friday night, with 40 of them killed in fire in the House of Trade Unions. Some 214 people have sought medical help.

Pro-Kiev radicals blocked the anti-government protesters in the Trade Unions House and set the building on fire. Some burned to death, while others suffocated or jumped out of windows.

Odessa prosecutor Igor Borshuliak told reporters at a press conference on Saturday that law enforcement officers have launched several inquiries, including into police professional negligence. A total of 144 persons have been detained as a part of criminal proceedings, Kyivpost reports.

Pro-federalization rallies have been on the rise in Ukraine's eastern cities of Kharkov, Lugansk and Donetsk since March. Later protests have spread to a number of cities in the Donetsk region.