MOSCOW — Russia’s security services have killed 49 rebels and have captured dozens more in a counterterrorism offensive that officials called a ‘‘considerable’’ blow to the insurgency in the North Caucasus region, the Russian National Anti-Terrorism Committee said Sunday.

President Vladimir Putin had urged the use of more aggressive means to subdue the insurgency in the North Caucasus before the 2014 Winter Olympics in the southern city Sochi, which is on the edge of the turbulent region.