The United States and South Korea are working together to find a diplomatic solution to North Korea's nuclear and missile problem, the State Department said Wednesday, as both Washington and Pyongyang appeared to take a step back from their bellicose rhetoric.

Just last week, US President Donald Trump promised to rain "fire and fury" on North Korea if it continued to threaten his country, leading some to believe the US could go to war with the provocative regime.

But South Korean President Moon Jae-in made clear in a Liberation Day address Tuesday that there would be no military action on the Korean Peninsula without Seoul's consent.

"The United States continues to be a steadfast ally, friend, and partner to the ROK and we continue to work closely with the ROK Government to find a diplomatic solution to the North Korean issue," Katina Adams, a State Department spokeswoman, said when asked to comment on the speech. ROK is an acronym of South Korea's official name, the Republic of Korea.

She also reaffirmed Washington's "ironclad commitment" to defend South Korea along with the American people and other allies.

"We remain fully prepared to deter, defend against, and respond to the threat posed by North Korea," she said.

North Korea threatened last week to fire ballistic missiles toward the US territory of Guam. On Tuesday, the country's leader, Kim Jong-un, put the plan on hold, saying he would watch Washington's behavior "a little more." (Yonhap)