North Korea fired two cruise missiles from the west coast town of Onchon early on Wednesday, a South Korean military source said.

The source added that the South Korean and the United States military authorities are analyzing details of the missiles' flight, including the range.

The launches come a day after Seoul and Washington kicked off four days of preliminary joint drills in preparation for the long-suspended live field training Ulchi Freedom Shield, which takes place from Aug. 22 to Sept. 1.

North Korea Missile Launch

This photo provided by the North Korean government shows what it says is a test launch of a hypersonic missile on Jan. 11, 2022, in North Korea. (Korean Central News Agency/Korea News Service via AP)

SOUTH KOREA DETECTS SHOTS APPARENTLY LAUNCHED BY NORTH KOREA

The two allies have scaled back combined military drills in recent years because of COVID-19 and to lower tensions with the North, which has accused the exercises of being a rehearsal for invasion.

Meanwhile, the Pentagon on Tuesday said the U.S., South Korea and Japan participated in a ballistic missile defense exercise off Hawaii's coast last week — the first such drills since 2017 as relations between Seoul and Tokyo hit their lowest in years.

North Korea flag next to barb wire

A North Korea flag flutters next to concertina wire at the North Korean embassy in Kuala Lumpur, Malaysia, on March 9, 2017. (Reuters/Edgar Su)

While Pyongyang has not conducted a missile test for two months, it had battled against a COVID-19 outbreak for months before declaring victory over the virus last week. The North, however, has been observed preparing for a possible nuclear test, which would be its first since 2017.

BROMANCE? PUTIN AND KIM TAKE ON THE WORLD, CRITICS FEAR UKRAINE WAR HAS BOOSTED ALLIANCE

Kim Jong Un at pharmacy

In this photo provided by the North Korean government, North Korean leader Kim Jong-un, center, visits a pharmacy in Pyongyang, North Korea, on May 15, 2022. (Korean Central News Agency/Korea News Service via AP, File)

CLICK HERE TO GET THE FOX NEWS APP

In a separate news release made by the North on Thursday, the sister of leader Kim Jong-un blamed propaganda leaflets from South Korea found near the border for causing the coronavirus outbreak and vowed a "deadly retaliation" against the South.

Despite such warnings, South Korean President Yoon Suk-yeol on Wednesday reiterated that he is willing to provide phased economic aid to North Korea if it ended nuclear weapons development and began denuclearization.