The U.S. Defense Department on Wednesday announced a new set of military exercises that will be held with South Korea off the west coast of the Korean Peninsula early next month.

Pentagon spokesman Bryan Whitman said U.S. and South Korean forces will participate in anti-submarine warfare exercises. He said it is too early to detail what surface ships, submarines and air units will participate.

The exercise will focus on anti-submarine warfare tactics, techniques and procedures, Whitman said, and "it will be conducted in the waters off the western coast of South Korea." He said the drills are "defensive in nature."

The drills will follow two sets of large-scale joint military exercises recently held by Seoul and Washington, under a framework agreed by top diplomats and defense officials from the two countries in late July.

At the so-called "two plus two" security talks, the two allies' foreign and defense ministers decided to stage a series of joint military drills, as countermeasures against the sinking of the South Korean warship Cheonan in March, which left 46 sailors dead. Seoul accused the Democratic People's Republic of Korea (DPRK) of torpedoing the warship, but Pyongyang denies its involvement.

After their four-day joint military drills, code-named " Invincible Spirit", in waters off the east coast of the divided Korean Peninsula late July, the two allies currently are carrying out 11-day war games dubbed the "Ulchi Freedom Guardian" (UFG).

On its part, Pyongyang has warned of counteractions against the UFG, criticizing it for heightening tension. It recently promised to deliver a "merciless counterblow" against the war games.