South Korea and the United States are set to end their two monthlong joint military exercises this week, but tensions are expected to go up further as North Korea is seen as preparing for another nuclear test, officials said Friday.

"The Foal Eagle exercise will officially wrap up its schedule tomorrow although its outdoor training programs are all to end today," a military official said.

The last day of the exercise on Saturday will be assigned to breaking up camps and withdrawing assembled military assets and troops, the official noted.

The allies had kicked off the annual field exercise on March 7, along with the Key Resolve command post exercise, which ran for two weeks.

This year's exercises were the biggest of their kinds, having come on the heels of North Korea's provocative nuclear test in January and a long-range rocket launch in February.

The two exercises brought together some 300,000 South Korean armed forces and 17,000 U.S. forces, along with the U.S. Navy's nuclear-propelled aircraft carrier USS John C. Stennis (CVN-74) and two Wasp-class amphibious assault vessels: the USS Bonhomme Richard (LHD 6) and the USS Boxer (LHD-4).

The latest exercises also integrated the allies' newly signed OPLAN 5015, which reportedly encompasses the option to pre-emptively strike North Korea's key military facilities and its leadership.

"In the biggest-ever South Korea-U.S. exercises, the allies demonstrated their strong determination to defend the Korean Peninsula through various readiness trainings in defense against North Korea intimidation," Defense Ministry spokesman Moon Sang-gyun told reporters.

"The exercises focused on the process of deploying reinforcements from the U.S. in the event of an emergency and intensifying South Korean troops' mission operability with their American partners," he added.

Unusually intensive protests from Pyongyang followed the alliance exercises, which the communist country has habitually denounced as a dress rehearsal for a war against North Korea.

North Korea launched a string of short- to mid-range missile launches during the course of the two-month exercise, including the firing of two Musudan intermediate-range ballistic missiles on Thursday. Both of them are believed to have exploded shortly after being launched.

During his trip to New York this week, North Korean Foreign Minister Ri Su-yong told reporters that if South Korea and the U.S. stop their joint exercises, the communist country would no longer carry out nuclear tests.

But U.S. President Barack Obama squarely dismissed the offer, saying that the allies had no plans to halt the military exercises.

North Korea is widely believed to be preparing its fifth nuclear test in the runup to the country's rare congress of the ruling Workers' Party of Korea set to begin on May 6.

"North Korea appears to have finished reparations (for the atomic test)," spokesman Moon told reporters earlier in the day. (Yonhap)