This file image, captured from the Twitter account of the U.S. Indo-Pacific Command, shows photos of South Korean and U.S. Marines engaging in combined drills at Rodriguez Live Fire Complex in Pocheon, 52 kilometers northeast of Seoul, April 5. Yonhap

The U.S. military has revealed it conducted "combined attack" drills with the Korean military earlier this month, in the allies' latest Marine training to bolster deterrence against growing North Korean threats.

In a tweet Monday, the Indo-Pacific Command disclosed a series of photos showing allied troops engaging in the drills at Rodriguez Live Fire Complex in Pocheon, 52 kilometers northeast of Seoul, on April 5.

The drills, part of the Korea Marine Exercise Program (KMEP), came as the allies are stepping up security coordination amid tensions heightened by the North's continued weapons tests, such as that of a purported solid-fuel intercontinental ballistic missile last Thursday.

One of the photos showed a U.S. Marine firing an M240B machine gun, while another depicted a Korean soldier conducting radio communications at an outdoor training site.

The command said that the "ironclad" alliance between Korean and U.S. Marines built "lethality" with the combined attack drills.

From late last month through early this month, the allies' Marine forces carried out their first large-scale Ssangyong (double dragon) amphibious landing exercise in five years under a joint push to strengthen combined drills to enhance readiness.

The two countries' Marines engage in 15 to 25 KMEP exercises each year. (Yonhap)