Heavily-armed gunmen in Chechnya attacked a police post early Thursday, killing several officers before storming buildings including a school in the capital Grozny

Heavily-armed gunmen in Chechnya attacked a police post early Thursday, killing several officers before storming buildings including a school in the capital Grozny.
  
The early morning raid came hours before President Vladimir Putin was to deliver his annual state of the nation address and weeks after a suicide blast shattered a period of relative calm in the volatile region.
  
One of the stormed buildings was ablaze, with thick smoke billowing into the sky from its eight storeys, as residents were told to stay indoors and security forces worked to root the gunmen out of a school nearby.
  
Automatic gunfire and heavy blasts rocked the city, according to video images posted by Russian media and on social networks. "There are still some of them sitting in a school," Chechnya's pro-Kremlin leader Ramzan Kadyrov said on the Echo of Moscow radio.
  
"We have them surrounded in the school area," he said, adding that the gunmen were "very heavily armed", including with grenade launchers.

The state RIA Novosti news agency, quoting a regional law enforcement source, said five police died and several were wounded.