Seoul, Jul 1 (IANS): North Korea fired an unidentified ballistic missile eastward on Monday, South Korea's military said, marking its second launch in a week.

The Joint Chiefs of Staff said it detected the launch but gave no further details, saying an analysis is underway.

The latest launch comes after North Korea fired a ballistic missile toward the East Sea on Wednesday, Yonhap news agency reported.

North Korea claimed to have successfully conducted a multiple warhead missile test, but South Korea has dismissed the claim, saying the launch failed as the missile exploded in the air.

The Joint Chiefs of Staff (JCS) said one short-range ballistic missile was launched from the Jangyon area in South Hwanghae province at about 5:05 a.m. in a northeastern direction. Another unidentified ballistic missile was launched at around 5:15 a.m.

It did not provide further details, such as how far the missiles flew, Yonhap news agency reported.

"While strengthening our monitoring and vigilance against additional launches, our military is maintaining a full-readiness posture while sharing North Korean ballistic missile data with US and Japanese authorities," the JCS told the media.

On Sunday, North Korea's Foreign Ministry denounced the three-day multi-domain "Freedom Shield" exercise, saying the country would take "offensive and overwhelming" countermeasures against what it called an attempt to strengthen a military bloc.

The drills, which ended on Saturday, involved fighter jets and warships, including a US aircraft carrier.

The latest launch came five days after North Korea fired a ballistic missile toward the East Sea on Wednesday.

North Korea claimed the next day to have successfully conducted a multiple warhead missile test, but South Korea has dismissed the claim as "deception", saying the launch failed as the missile exploded in midair.

North Korea has ratcheted up cross-border tensions in recent weeks, launching trash-carrying balloons to South Korea in a tit-for-tat move against anti-Pyongyang leaflets sent by North Korean defectors and activists in South Korea.

The latest launch also took place amid growing concerns over deepening military cooperation between Pyongyang and Moscow after North Korean leader Kim Jong-un and Russian President Vladimir Putin signed a "comprehensive strategic partnership" treaty during a summit last month in Pyongyang.

The pact includes a pledge for the two countries to come to each other's aid if attacked.