North Korea fired two cruise missiles into the sea off its east coast  South Korea’s military said, amid rising tension over a recent series of weapons tests.

South Korea’s Joint Chiefs of Staff did not specify the missiles’ range or trajectory, but said it was conducting an analysis together with U.S. authorities.

The launch was North Korea’s fifth of the year, following tests of a tactical guided missile , two “hypersonic missiles” capable of high speed and manoeuvring after lift-off, and a railway-borne missile system.

Tension has been growing, with leader Kim Jong Un vowing last week to bolster the military and warning he could lift a self-imposed moratorium on testing atomic bombs and long-range missiles.

North Korea has not launched intercontinental ballistic missiles or nuclear weapons since 2017, but began testing a slew of shorter-range missiles after denuclearisation talks stalled following a failed summit with the United States in 2019.

The flurry of recent tests sparked a U.S. push for fresh U.N. sanctions, followed by heated reaction from Pyongyang.

The U.N. Security Council bans North Korea from any launches using ballistic technology, but not cruise missiles. China and Russia have recently called for removing a ban on Pyongyang’s exports of statues, seafood and textiles, and raising a refined oil imports cap.

South Korea’s Unification Minister Lee In-young, in charge of cross-border ties, urged the North to return to talks, not escalate further.

“While thoroughly preparing for additional tests, we’d like to emphasise again that dialogue and cooperation is the only way to peace,” he told a meeting with foreign diplomats based in Seoul.

Japan’s Chief Cabinet Secretary Hirokazu Matsuno did not confirm the latest test but said Tokyo would work with neighbours to gather and analyse necessary information.

Lee Sang-min, a military expert at the Korea Institute for Defense Analyses, said the recent missile volleys could be aimed at building geopolitical tensions and perhaps pushing the United States to come up with a new strategy toward Kim.

“Cruise missiles are slower than ballistic missiles and so are regarded as less of a threat, but they hit targets with high precision, something North Korea would continue to develop,” Lee said.

North Korea has said it is open to talks, but only if the United States and its allies drop “hostile policy” measures such as sanctions and military drills.