SEOUL, South Korea — North Korea fired a ballistic missile on Wednesday morning for the first time in more than two months, defying demands from President Trump to halt its weapons programs and raising the stakes in an increasingly tense standoff with the United States and its allies.

“North Korea launched an unidentified ballistic missile eastward from the vicinity of Pyongsong, South Pyongan Province, at dawn today,” the South Korean Joint Chiefs of Staff said in a statement. Pyongsong, in western North Korea, is about 20 miles northeast of Pyongyang, the capital.

The launch was also confirmed by the Japanese prime minister’s office.

The new missile firing came as North Korea has increased the frequency and daring of its missile tests, sending two missiles over Japan in August and September, while showing technical progress that suggested it had developed the ability to strike the continental United States.

In a Sept. 19 speech at the United Nations, Mr. Trump warned that if North Korea threatened the United States or its allies, Washington would have “no choice but to totally destroy North Korea,” and he mockingly referred to its leader, Kim Jong-un, as “rocket man.”

The North Korean leader responded by calling Mr. Trump “a mentally deranged U.S. dotard,” and his foreign minister later warned that Mr. Kim could order the test of a hydrogen bomb over the Pacific.

In the wake of a Sept. 3 underground nuclear test — the sixth by North Korea — the United Nations Security Council imposed a new round of sanctions against the country.

In the nearly three months since that test, as leaders of North Korea and the United States have exchanged insults, the world has braced itself for another show of force by the North.

While in New York for the United Nations General Assembly meeting in September, North Korea’s foreign minister, Ri Yong-ho, said that Mr. Kim was considering a hydrogen bomb test of unprecedented scale over the Pacific Ocean.

North Korea has persisted in its nuclear weapons and missile development despite nine rounds of sanctions that the Security Council has imposed since its first nuclear test in 2006. The country has also made strides in its ballistic missile program since Mr. Kim took power in late 2011. It tested two intercontinental ballistic missiles, or ICBMs, in July, the last of which demonstrated the potential of reaching the mainland United States.

Washington is applying what it calls “maximum pressure and sanctions” to stop North Korea from reaching the stage where it would be able to deliver a nuclear warhead on its ICBMs. But Mr. Kim says his country will conduct more missile tests in the Pacific Ocean to hone its capabilities.