SEOUL, Feb 17 (Reuters) - North Korea threatened on Friday to take "unprecedentedly constant, strong responses" if South Korea and the United States press ahead with planned military drills, accusing the allies of raising tensions in the region.

In a statement carried by state media KCNA, the North's foreign ministry also said it would consider additional military action if the U.N. Security Council, under the influence of the United States, continues to pressure Pyongyang.

The statement came as South Korea and the United States gear up for annual military exercises as part of efforts to better counter North Korea's growing nuclear and missile threats.

The allies will stage tabletop exercises in Washington next week aimed at improving operations of American nuclear assets and hold regular springtime Freedom Shield drills next month in South Korea, Seoul's defence ministry said on Friday.