Russia discovers 12 World Cup terror attack plots as FSB kills 15 in race to stop Isis

Half a dozen specific terror plots were thwarted, said Alexander Bortnikov, the head of the FSB security service. 

“The activities of 12 secret terrorist cells were halted,” he added. 

The 15 were slain in several operations hen they resisted arrest. 

This week Isis warned that Vladimir Putin “will pay the price for killing Muslims” in a chilling propaganda poster. 

The FSB has identified terrorism as the biggest threat to the World Cup in June and July. 

But he also revealed a massive increase in security on the bridge, now under construction, connecting the Russian mainland to the Crimea peninsula, annexed from Ukraine by Putin using military force in 2014. 

"Law enforcement agencies have organised monitoring of the situation in the Kerch Strait and the skies above,” he said.

“Their forces and hardware stand ready for coordinated action in case there is a terrorist threat to the unfinished facilities.”

He said: ”In all, 189 militants and their accomplices have been detained and another 15 have been neutralised since the beginning of the year,” said the head of the FSB, an agency once led by Putin. 

Last month, FSB agents smashed their way into 16 addresses  in Krasnoyarsk, with nine alleged jihadists detained, three organisers and six cell members. 

Two were grabbed as they sought to board a flight. 

Also in March, four jihadists in a sleeper unit were detained in Kaluga region, allegedly  preparing attacks in or near Moscow.

Separately, the FSB “eliminated” an Isis terrorist cell in a highway shootout some 235 miles from where England play in Volgograd in June. 

One gun-toting alleged terrorist was shown holding a pistol as he lay in snow.

It was not clear how many alleged terrorists had been killed in the shootout.

Two bodies were visible in footage and pictures.