A new ROK-US pact providing for a joint military response "even to low-level provocation" by Pyongyang offers an added deterrent at a time of elevated tension, Seoul's Defense Ministry said on Monday.

The two countries signed the military agreement on Friday in a move likely to fuel fresh outrage in the Democratic People's Republic of Korea, which has spent the past few weeks denouncing joint ROK-US military exercises.

While existing agreements provide for US engagement in the event of a full-scale conflict, the new protocol addresses the response to a "low-level action" such as a limited cross-border incursion.

It guarantees US support for any retaliation from the Republic of Korea and allows Seoul to request any additional US military force it deems necessary.

"This allows both nations to jointly respond to Pyongyang's local provocations, with Seoul taking the lead and the US in support," ROK Defense Ministry spokesman Kim Min-seok said.

"It will have the effect of preventing Pyongyang from daring to provoke us," Kim told reporters.

The United States has about 30,000 troops stationed in the ROK with the option to bring in reinforcements from its military bases in Japan.

The "provocative" scenarios envisaged by the new pact include maritime border incursions, shelling of border islands and infiltration by low-flying fighter jets or by special-forces units.

The chairman of the ROK Joint Chiefs of Staff, General Jung Seung-jo, said the accord would allow "strong retaliation" that would make the DPRK "bitterly regret" any provocative move.

The protocol was signed just days before the third anniversary of the 2010 sinking of the ROK naval corvette, Cheonan, with the loss of 46 lives.

The ROK said it was sunk by a DPRK torpedo, although Pyongyang has denied any involvement.

Later the same year, Pyongyang shelled the ROK border island of Yeonpyeong, killing four people.

Angered by UN sanctions imposed after its nuclear test in February, Pyongyang has issued a wave of threats over the past month - ranging from a surgical military strike to nuclear war.

DPRK leader Kim Jong-un recently made a series of visits to frontline military units across the country, during which he threatened to "wipe out" ROK military units on another border island.

On Tuesday, ROK President Park Geun-hye and top military officials were scheduled to attend a memorial ceremony at the national cemetery in Daejeon, where the victims of the Cheonan sinking are buried.