North Korea fired two unidentified short-range projectiles into the sea off its eastern coast on Friday, South Korea's Joint Chiefs of Staff said, in its third series of launches in a little over a week.

The projectiles launched from South Hamgyong Province at 2:59 a.m. and 3:23 a.m., respectively, flew about 220 kilometers and reached an altitude of about 25 km and a speed of Mach 6.9, the JCS said, adding it is on the lookout for possible further launches.

South Korean and U.S. authorities believe they were a new type of short-range ballistic missile and are working to further analyze the projectiles, South Korean presidential spokeswoman Ko Min Jung said.

U.S. media reports, citing government officials, said the projectiles fired into the Sea of Japan are believed to be short-range ballistic missiles similar to those test-fired by North Korea in the past eight days.

In Tokyo, a government source said Japan shared the U.S. assessment.

[Photo courtesy of Korean Media]

Related coverage:

N. Korean leader Kim oversaw launch of new type of rocket: KCNA

N. Korea fires 2 short-range ballistic missiles

Pyongyang residents voice support for anti-S. Korea missile launch

North Korea, however, has said that projectiles it launched on Wednesday were a "newly-developed large-caliber multiple launch guided rocket system."

The country also fired two short-range ballistic missiles into the Sea of Japan on July 25. Its media said they were a "new-type tactical guided weapon" and intended as a warning against South Korea's planned joint military exercise with the United States this month.

The Japanese government said it has confirmed that neither projectile fired early Friday fell into its territorial waters or within its exclusive economic zone.

Amid stalled talks on North Korea's denuclearization, U.S. President Donald Trump again downplayed the latest launches, although U.N. Security Council resolutions ban Pyongyang from the use of ballistic technology.

"I think it's very much under control, very much under control," Trump told reporters at the White House.

"We never made an agreement on that. I have no problem," said Trump, who met with North Korean leader Kim Jong Un in late June and agreed with him to revive the negotiations. "We'll see what happens. But these are short-range missiles. They are very standard."

"We never discussed that. We discussed nuclear. What we talked about is nuclear," he said.