The US flew bombers near North Korea’s coast on Saturday, an action the Defense Department said was meant to send a clear message to Pyongyang about the country’s military options.

“This mission is a demonstration of US resolve and a clear message that (President Donald Trump) has many military options to defeat any threat,” Pentagon spokeswoman Dana White said in a statement, Efe news reported.

“North Korea’s weapons program is a grave threat to the Asia-Pacific region and the entire international community. We are prepared to use the full range of military capabilities to defend the US homeland and our allies,” the statement added.

White said US Air Force B-1B bombers from the US island territory of Guam and US Air Force F-15C Eagle fighter escorts from Okinawa, Japan “flew in international airspace over waters east of North Korea.”

“This is the farthest north of the Demilitarized Zone (DMZ) any US fighter or bomber aircraft have flown off North Korea’s coast in the 21st century, underscoring the seriousness with which we take (North Korea’s) reckless behavior,” White said.

The Pentagon’s announcement came before North Korea addressed the United Nations’ General Assembly on Saturday and after the US imposed new sanctions on Pyongyang this week.

Those new sanctions bar ships and aircraft from visiting the US within 180 days of having gone to North Korea.

The ban also applies to vessels that have done a ship-to-ship transfer with a vessel that has visited North Korea within 180 days.

Trump ordered the sanctions via a decree whose aim is to “maximize pressure on North Korea to demonstrate to its leadership that the best and only path is to return to denuclearization.”

A new nuclear test by Pyongyang earlier this month and Trump’s belligerent rhetoric have caused tensions on the Korean peninsula to soar over the last year.

Seismic activity Saturday in North Korea, meanwhile, sparked fears that Pyongyang may have conducted yet another nuclear test, but experts said the small earthquake was probably due to natural causes.

North Korea has refused to back down in the face of international pressure and on Saturday said it was nearing completion of its nuclear goals but that its program was intended merely as a deterrent.

“We do not have any intention at all to use or threaten to use nuclear weapons against the countries that do not join in the US military actions against (the Asian nation),” North Korean Foreign Minister Ri Yong-ho told the UN General Assembly on Saturday.

Ri on Friday said North Korea may test a hydrogen bomb in the Pacific Ocean, making those remarks after Trump inflamed tensions in his debut speech before the UN.

Trump ominously warned Pyongyang on Tuesday that the US would obliterate the Asian country if necessary.

“The United States has great strength and patience, but if it is forced to defend itself or its allies, we will have no choice but to totally destroy North Korea,” Trump said in his UN speech.