North Korea fired what appeared to be short-range ballistic missiles twice on Friday, Aug. 2, into the sea off its eastern coast in its third round of weapons tests in just over a week, South Korea’s military and presidential office said, according to AP.

The increased testing activity is seen as brinkmanship aimed at increasing pressure on Seoul and Washington over stalled nuclear negotiations. North Korea has also expressed frustration at planned U.S.-South Korea military exercises, and experts say its weapons displays could intensify in coming months if progress on the nuclear negotiations isn’t made, AP reported.

By test-firing weapons that directly threaten South Korea but not the U.S. mainland or its Pacific territories, North Korea may also be trying to dial up pressure on Seoul and test how far Washington will tolerate its bellicosity without actually causing the nuclear negotiations to collapse, AP wrote.

“Maybe North Korea wants to try to push the U.S. back to the negotiating table with some kind of proposal for weakening sanctions,” said Yoichi Shimada, professor of international politics at Japan’s Fukui Prefectural University. But Shimada believed President Trump would not hold back on economic sanctions, “despite all the friendly talk about Kim,” according to the Guardian. 

Garren Mulloy, professor of international relations at Daito Bunka University in Japan, views actions from the North as an attempt to exploit “obvious weaknesses in the U.S.-Japan-South Korea relationship. … So Chairman Kim is hoping to make more trouble and demonstrate that he can act with impunity.” 

“North Korea is looking for a window of opportunity, a crack in the door,” said Mulloy. “It is always focused on the U.S.—it’s never really about Japan and South Korea, even when it looks like it is. Everything the DPRK wants is to be treated like a great power by the great power,” according to the Guardian. 

President Trump seemed to downplay the tests. On Thursday, President Trump told reporters about two previous missile tests by North Korea. 

 “I think it’s very much under control. Very much under control,” President Trump said. 

“Short-range missiles. We never made an agreement on that. I have no problem. We’ll see what happens. But these are short-range missiles. They’re very standard,” the President added. 

Includes reporting from The Associated Press