South Korea and the United States wrapped up Tuesday their joint military drills which was denounced by the Democratic People's Republic of Korea(DPRK)as "an irresponsible and dangerous action."

The two-month Foal Eagle exercises, launched on March 1, were aimed to improve the readiness of US-South Korea alliance to defend South Korea, with 10,000 US troops and 200,000 South Korean troops involved.

The United States deployed nuclear-capable weapons during this year's joint military exercise, including two B-22 bombers.Two B-2 Spirit Bombers were sent from Whiteman Air Force Base in the US state of Missouri to the Korean Peninsula to carry out its first firing drill in South Korea. F-22 Raptor fighters and MV-22 Ospreys also joined the exercise.

Ahead of the exercises, the DPRK had successfully conducted a third nuclear tests on February 12,T which drew condemnation from the international community. The United States and some other countries are pressing for stricter sanctions against Pyongyang at the UN Security Council.

The DPRK strongly protested the Foal Eagle exercises, but the US-led Combined Forces Command(CFC) insisted on continuing the military exercises, describing them as defensive in nature and unrelated to DPRK's recent nuclear test.

Soon afterwards the DPRK vowed to nullify an armistice that ended the 1950-53 Korean War from March 11, and warned of more and stronger countermeasures if the United States and South Korea continued joint military drills.

Tensions have escalated sharply on the Korean Peninsula as the US Air Force's B-2 stealth bombers conducted its first- ever firing drill in South Korea on March 28.

"As the B-2 has radar-evading stealth function, it can penetrate the anti-aircraft defense to drop conventional and nuclear weapons,"South Korean Yonhap News Agency quoted a senior military official as saying. "It is the strategic weapon most feared by North Korea (DPRK)."

Two days later,Pyongyang said it had entered a "state of war" with South Korea and threatened to shut down their joint industrial park located in the DPRK's border city of Kaesong.

South Korean President Park Geun-hye said on April 1 that she " sees the recent DPRK's threat very seriously," and ordered the military to respond strongly to possible provocation by the DPRK without any political considerations over DPRK's recent threats.

Situations in the conflict-prone regions near the "Northern Limit Line" and the Military Demarcation Line has worsened since Pyongyang banned the entry of South Korean workers to the Kaesong Industrial Park, allowing only for their departure from Kaesong on April 3.

South Korean Unification Minister Kihl-jae said that Seoul has had its door open for dialogue with Pyongyang, urging the DPRK to normalize passage to Kaesong complex.

The DPRK withdrew all its 53,000 workers from the industrial zone on April 9 in defiance of South Korea's protests. The operations of 123 South Korean companies in Kaesong Industrial Complex has been halted since then.

Two weeks after suspensions of South Korean companies in Kaesong, South Korea proposed talks with the DPRK. But the DPRK rejected Seoul's proposal and warned of decisive action if South Korea keeps aggravating the situation.

Following the DPRK's response, South Korea decided to withdraw all their workers in Keasong last week. South Korea has pulled out all but seven of its workers in the early morning of Tuesday.

Kaesong Industrial Complex, an important symbol of inter-Korean economic cooperation, faces closure amid tensions on the peninsula.