North Korea on Saturday extended a recent streak of weapons display by firing projectiles twice into the sea, according to South Korea’s military.

It’s the fifth round of weapons launches in less three weeks was likely another protest at the slow pace of nuclear negotiations with the United States and continuance of U.S.-South Korea joint military exercises the North says are aimed at a northward invasion.

South Korea’s Joint Chiefs of Staff said the unidentified projectiles were fired from an area on the North’s eastern coast, but did not immediately confirm how many were launched or how far they flew.

The North has unleashed a series of test firings of short-range weapons in recent weeks while saying that the joint military drills between the allies compels it to “develop, test and deploy the powerful physical means essential for national defence.”

The North did not immediately comment on the launches. South Korea has said the North’s recent weapons tests don’t help efforts to stabilize peace and called for Pyongyang to uphold an inter-Korean agreement reached last year to form a joint military committee to discuss reducing military tensions.

The North Korean missile tests, which U.S. President Donald Trump has repeatedly played down, come amid stalled diplomatic talks with the United States on the North’s nuclear program. So far, North Korea has stuck by its unilateral suspension of nuclear and long-range missile tests, which came during a diplomatic outreach to Washington last year.

Experts say Trump’s downplaying of the North’s launches allowed the country more room to intensify its testing activity while it seeks to build leverage ahead of negotiations, which could possibly resume sometime after the end of the allies’ drills later this month.

The North described recent test-firings as a new rocket artillery system and short-range ballistic missile launches. The North’s state media said leader Kim Jong-un while supervising a live-fire demonstration of newly developed, short-range ballistic missiles on Tuesday said the launches were intended to send a warning to Washington and Seoul over their military drills.