There is a firefight going on outside the building of the Security Service of Ukraine's (SBU) office in Donetsk region, which wasseized by the supporters of self-proclaimed 'Donetsk People's Republic', Donetsk mayor Oleksandr Lukyanenko said.

"One can hear shooting near the security office in Donetsk region on Schorsa Street. We're asking residents of neighboring houses not to approach the houses, not to come on the balconies or the street without extreme necessity," the city mayor said in a report posted on his Web site on Wednesday.

What is more, two combat aircraft are flying above the central districts of the city – Kyivsky and Voroshylovsky. There is a huge buzz in the city, the witnesses told Interfax.

They said that there are sounds of shooting near the regional traumatology department, and a part of offices in this area have stopped their work.