The mayor of Ukraine’s second-largest city was shot in the back yesterday as elsewhere pro-Russia activists seized yet another government building.

Kharkiv Mayor Hennady Kernes was shot this morning, his office said.

He was said to be undergoing surgery and “doctors are fighting for his life,” according to the city hall.

Spokesman Yuri Sydorenko said that the attack occurred on the outskirts of the city, but officials have not commented on who was behind it.

Mr Kernes was a staunch opponent of the pro-West Maidan movement that toppled president Viktor Yanukovych in February and was the organiser of activists sent to Kiev from eastern Ukraine to oppose the demonstrators.

But he has since softened his stance toward the new government. 

At a meeting of eastern Ukrainian leaders with acting Prime Minister Arseniy Yatsenyuk earlier this month, Mr Kernes insisted he did not support the pro-Russia activists and backed a united Ukraine.

Kharkiv is in eastern Ukraine, but unlike the neighbouring Donetsk region, the city has been largely unaffected by the pro-Russian actions. 

Its regional administration building was briefly seized earlier this month but promptly cleared of pro-Russian protesters.

In the industrial city of Kostyantynivka, 100 miles from the Russian border and 22 miles south of Slovyansk, masked activists with automatic weapons seized another city hall building and a police station.

The city has been in pro-Russian activists’ hands for more than three weeks.

After the seizure, about 15 armed men guarded the city hall building and posed for pictures with residents.

Outside the country, US President Barack Obama said that he would increase pressure on Russia with further sanctions, including on high-technology exports to Russia’s defence industry. 

The full list included seven wealthy allies of President Putin and 17 Russian companies.

The European Union is also planning more sanctions, with ambassadors from the bloc’s 28 member states meeting in Brussels yesterday to add to the list of Russian officials who have been hit by asset freezes and travel bans.