The South Korean army has begun what it claims to be its largest land and air winter drills in Pocheon city, about 20 miles from North Korea.

The drills will involve more than 800 military personnel and include six fighter jets, anti-tank missiles and more than 100 types of weapons, according to an army spokesperson.

The exercises, planned in 2009, have come after North Korea recently shelled a South Korean island in the Yellow Sea, resulting in four deaths.

North Korea has ruled out any retaliation in the wake of the latest drills but has issued a warning to South Korea and the US, according to the state-run Korean Central News Agency.