North Korea's latest round of missile launches is widely seen as an attempt to step up pressure on Washington at a moment of high-profile international diplomacy and renewed chatter about possible US-North Korea talks.

Pyongyang fired two short-range ballistic missiles from the Wonsan area into the East Sea on Sunday. According to Seoul's Joint Chiefs of Staff, the first weapon, launched around 3 p.m., flew roughly 450 kilometers, while the second, at about 5:50 p.m., traveled more than 600 kilometers.

The timing of the launches has drawn scrutiny because they came just days before the UN General Assembly convenes in New York on Tuesday and ahead of a summit between US President Donald Trump and Chinese President Xi Jinping.

South Korean President Lee Jae Myung is due to attend the UN gathering, where he is expected to lay out his administration's vision for peace and coexistence on the Korean Peninsula. At last year's assembly, Lee introduced his “E.N.D. Initiative,” which emphasizes exchange, normalization and denuclearization, with an early priority on slowing the advancement of the North's nuclear and missile programs.

Against that backdrop, the missile tests could be read as Pyongyang's way of restating its refusal to negotiate on the basis of denuclearization and demanding recognition as a nuclear-armed state in any future dialogue with Washington.

The launches also precede Thursday's US-China summit, where North Korea could once again surface as a point of friction between Trump and Xi. At their previous meeting in Beijing in May, China did not publicly say whether the North's nuclear program came up. Trump, however, later said the two leaders had discussed the denuclearization of North Korea.

Pyongyang may be especially wary of any sign that Beijing, its longtime ally and primary economic backer, remains committed to the broader goal of a nuclear-free Korean Peninsula.

Trump has repeatedly voiced a willingness to reengage with North Korean leader Kim Jong-un, fueling speculation that summit diplomacy between Washington and Pyongyang could resume.

Under that reading, Sunday's missiles could be aimed at establishing Pyongyang's preferred starting point for any future talks: that negotiations should center on issues other than giving up its nuclear arsenal.

“North Korea has repeatedly followed a pattern of launching missiles after criticizing South Korea-US and South Korea-US-Japan military exercises through statements by Kim Yo-jong and others,” said Yang Moo-jin, a distinguished professor at the University of North Korean Studies.

“The choice to launch short-range missiles toward the East Sea appears intended to demonstrate its short-range strike capabilities against South Korea and US Forces Korea while putting pressure on Washington ahead of any potential US-North Korea dialogue,” Yang said.

“In terms of timing, it also appears aimed at signaling ahead of the UN General Assembly that denuclearization is not an option.”

The launches came two days after Kim Yo-jong, the sister of North Korean leader Kim Jong-un, condemned the US-led multinational Pacific Vanguard maritime drills and warned that Pyongyang would respond with action that could be proportionate or stronger.

The North has stepped up its criticism of major military exercises involving South Korea, the United States and Japan in recent weeks. Its previous ballistic missile launch on Sept. 12 came a day after the three countries wrapped up their trilateral Freedom Edge exercise.

North Korean state media, meanwhile, remained silent about the latest launches on Monday.

The Korean Central News Agency made no mention of the two missiles early Monday, continuing an increasingly inconsistent pattern in which Pyongyang has sometimes chosen not to publicly report its weapons tests. Three missile launches last month went unreported by state media, while the Sept. 12 launch was disclosed two days later as part of a joint firepower strike drill involving artillery and missile units.

Asked about the silence, Seoul's Unification Ministry spokesperson Yoon Min-ho said Monday that the government would not read too much into it.

“There have been several instances in the past in which such launches were not reported, so we will not offer a separate assessment,” Yoon said during a regular briefing.

The US military also played down any immediate threat while reaffirming its defense commitments.

“We are aware of the recent missile launches and are consulting closely with our allies and partners,” US Pacific Command said in a statement posted on its website Sunday.

“Based on current assessments, these events do not pose an immediate threat to US personnel or territory, or to our allies. The United States remains committed to the defense of the US homeland and our allies in the region.”

Pacific Command has issued similarly worded statements after earlier North Korean missile launches this year, without explicitly condemning them.