US Department of Defense Press Secretary John Kirby (R) is seen taking questions in a press briefing at the Pentagon in Washington on Monday in this image captured from the department's website. (US Department of Defense)

WASHINGTON -- The United States is continuing to closely monitor North Korea for signs of additional provocations while sharing such intelligence with South Korea, a US Department of Defense spokesperson said Monday.

John Kirby said the US is also always looking for ways to get better information about the reclusive country.

US Indo-Pacific Command was ordered to intensify its intelligence, surveillance and reconnaissance (ISR) collection activities in waters near the Korean Peninsula in early March following a series of North Korean missile tests.

"Without getting into specific intelligence issues ... you saw us talk about increased ISR capabilities that we were going to be applying in the wake of these now multiple recent tests by the North Koreans and we're still doing that," the Pentagon press secretary said in a press briefing.

"And we're constantly looking for ways to get smarter and to get better information, as well as to make sure we're sharing that with the South Koreans," added Kirby.

Pyongyang has staged more than a dozen rounds of missile launches since September, including its first intercontinental ballistic missile launch in more than four years in March.

Officials in Seoul have also noted the North appeared to be repairing underground tunnels at its Punggye-ri nuclear test site that it purportedly demolished in 2018 to show its willingness to denuclearize, indicating a possible nuclear test down the road.

North Korea has so far conducted six nuclear tests, all at the Punggye-ri site. Its last nuclear test was in September 2017. (Yonhap)