WASHINGTON (REUTERS, BLOOMBERG) - The North Korean projectiles launched early Friday (Aug 2) appeared to be new short-range ballistic missiles, South Korea's government said.

The missiles flew 220 km (135 miles) and reached an altitude of 25 km (15 miles), the Joint Chiefs of Staff (JCS) in Seoul said.

US officials said earlier that North Korea had carried out a new projectile launch, adding that initial information indicated the launches were similar to two recent short-range tests carried out by Pyongyang.

South Korea's military said unidentified short-range projectiles were fired at 2.59am and 3.23am local time on Friday, from North Korea's South Hamgyong Province into the East Sea.

"We are monitoring the situation in case of additional launches and maintaining a readiness posture," South Korea's Yonhap news agency quotes the country's joint chiefs of staff as saying.

A US official, speaking on condition of anonymity, said at least one projectile was detected that did not pose a threat to North America, although there could have been multiple projectiles.

The Japanese Ministry of Defence said on Friday no immediate impact was seen on the nation's security after North Korea carried out a new projectile launch.

No ballistic missiles had reached Japan's territory or its exclusive economic zone after the launch, the ministry said in a statement.

North Korea fired two short-range ballistic missiles early on Wednesday, only days after it launched two similar missiles on July 25.

US President Trump played down the launches when asked about them at the White House just after news broke about the latest projectile launch.

He told reporters he was not worried as they were short-range and "very standard".

Asked at the White House before setting off for a campaign trip to Ohio if he thought North Korean leader Kim Jong Un was testing him, Trump said the launches did not violate the North Korean leader's promises to him.

"I think it's very much under control, very much under control," he told reporters. They were "short-range missiles," Trump said. "We never made an agreement on that. I have no problem. We'll see what happens. But these are short-range missiles. They are very standard."

Asked if he could still negotiate with Kim, he replied: "Oh, sure, sure. Because these are short-range missiles. We never discussed that. We discussed nuclear. What we talked about is nuclear. Those are short-range missiles. Sure, and a lot of other countries test that kind of missile also."

However, US Secretary of State Michael Pompeo told Bloomberg TV's Haslinda Amin that the US was concerned with North Korea's missile tests on Thursday morning and on Wednesday, while stressing that America's sanctions regime against Pyongyang was the "toughest stance in history."

He also said talks between the US and North Korea were ongoing despite Pyongyang's decision to have its foreign minister skip a potential meeting on the sidelines of a high-level regional forum in Thailand.

"You should never doubt what we are communicating to North Korea, there are conversations going on even as we speak," he said.

But he noted the diplomatic road is often a bumpy one.

"We are still fully committed to achieving the outcome that we laid out, for a fully, verified denuclearisation of North Korea, and to do so through the measure of diplomacy."

Earlier on Thursday and before the latest launch, US national security adviser John Bolton said North Korea's latest missile launches did not violate a pledge that Kim made to Trump not to test long-range missiles and nuclear weapons.

The two leaders agreed at a June 30 meeting to revive stalled denuclearisation talks, but efforts to resume the negotiations remain in doubt.

Diplomats have crisscrossed the region this week in the hope of restarting the talks and the North Korea launches have appeared intended to put pressure on South Korea and the United States to stop planned military exercises and offer other concessions.

A summit between Trump and Kim in Vietnam in February collapsed after the two sides failed to reconcile differences between US demands for North Korea's complete denuclearisation and North Korean demands for sanctions relief.

Bolton told Fox Business Network that while the launches did not violate Kim's pledge, "you have to ask when the real diplomacy is going to begin, when the working-level discussions on denuclearisation will begin."

"We've been waiting to hear since June the 30th," he told the network in a subsequent interview.

"We're ready for working-level negotiations. The president's ready, when the time is right, for another summit. Let's hear from North Korea."

At the United Nations on Thursday, Britain, France and Germany called on North Korea to engage in "meaningful" talks with the United States and said international sanctions needed to be fully enforced until Pyongyang dismantled its nuclear and ballistic missile programmes.

Their statement came after a closed-door UN Security Council meeting on the latest launches.