South Korea and U.S. officials vowed "strong punitive steps" against Kim Jong Un's regime if it continued provocations after North Korea appeared to conduct a failed missile test on Wednesday.

Meeting in Seoul, Kim Hong-kyun, South Korea's special representative for Korean Peninsula peace and security affairs, and his U.S. counterpart Joseph Yun reaffirmed a commitment to push Kim harder to drop its push for nuclear weapons. Recent provocations are probably a prelude to the launch of an intercontinental ballistic missile, according to a South Korean foreign ministry statement.

The South Korean defense ministry earlier said that North Korea appeared to have fired an unidentified missile from its Wonsan air base in the east. If confirmed, it would be the third round of missile tests by North Korea this year, as it seeks to develop the capability to deliver a nuclear weapon to the U.S. in defiance of United Nations sanctions.

South Korea's Kim and the U.S.'s Yun agreed that all countries including China must strictly implement U.N. sanctions against North Korea, according to the foreign ministry. They said that it's important to cut off sources of the regime's foreign-currency income and limit the activity of its people working abroad to further isolate it diplomatically and economically.

Kim, who has launched a series of projectiles and conducted three nuclear tests since he came to power more than five years ago, claimed in January to be in the final stage of preparations to test-fire an ICBM. North Korea fired four missiles this month that reached as far as Japan's exclusive economic zone.

The Trump administration has taken a harder line toward the regime, with Secretary of State Rex Tillerson saying last week that all options, including military, are on the table. On a trip to North Asia, Tillerson said 20 years of diplomatic efforts had failed to counter North Korea's nuclear program and he didn't rule out a preemptive strike.

President Donald Trump has said repeatedly that Kim is behaving "very badly" and China has done little to bring its neighbor into line. China, North Korea's closest ally and biggest trading partner, banned coal imports from the nation earlier this year.

North Korea responded to Tillerson's visit by saying it's not afraid of his stance and the U.S. needs to understand its pursuit of a nuclear deterrent, according to KCNA. Last weekend, Kim's regime hailed the ground test of a high-thrust engine that it said was developed for its space program.

Tillerson's suggestion the U.S. would consider military options isn't realistic given the ability of North Korea to retaliate and inflict immeasurable damage on the densely packed South Korean population, according to Robert Kelly, a political science associate professor at South Korea's Pusan National University.

"The military option sounds like Trumpian-alpha-male bravado to me," Kelly said. "The Trump people don't really have a strategy. They say there's a policy review, but who is leading it?"

North Korea began this year's launches by firing an intermediate-range Pukguksong-2 ballistic missile in February, drawing a joint rebuke from Trump and Japanese Prime Minister Shinzo Abe, who were meeting in Florida.

Kim's regime fired at least 25 projectiles in 2016, according to the U.N., which bans it from pursuing ballistic missile technology because it could be used to deliver nuclear warheads. Pyongyang also detonated two nuclear devices last year.