The United States said Sunday it is firmly committed to South Korea's security as South and North Korea were struggling in high-level talks to defuse the worst military tensions in more than two years.

"We are carefully monitoring the situation. We will continue to coordinate closely with the ROK and remain steadfast in our commitment to the defense of our allies," Gabrielle Price, a State Department spokeswoman, said in comments sent to Yonhap News Agency.

Top security officials of the two Koreas resumed crisis talks on Sunday after failing to find a compromise in the first round of talks. Though nearly 12 hours has passed since the talks resumed at the border village of Panmunjom, there were no signs the sides are close to agreement.

Tensions between the two Koreas began rising after an investigation found that the North secretly planted landmines on the southern side of the border, which exploded and severely injured two South Korean soldiers early this month.

The South retaliated by resuming anti-Pyongyang propaganda broadcasts along the border, dealing a blow to one of the sore points for a regime underpinned by the tight control of information. An angered North Korea fired artillery rounds with the South earlier this week, which led to a rare exchange of fire between the two sides.

North Korea had threatened to take strong military action unless the South halts the broadcasts and dismantles loudspeaker facilities by Saturday afternoon. But just hours before the deadline, the North proposed to hold talks to defuse the crisis. (Yonhap)