U.S. Secretary of Defense Chuck Hagel urged North Korea Monday to discontinue its "dangerous" provocations, hours after receiving a briefing on soaring tensions on the peninsula from his top military commander there.

"The provocation that the North Koreans have once again engaged in is dangerous and it needs to stop," the secretary said at a Pentagon press conference.

He said he had been briefed two hours earlier by Army Gen. Curtis Scaparrotti, chief of 28,500 U.S. troops in Korea, about the exchange of hundreds of rounds of artillery shells between the two Koreas on Monday (local time).

In hours-long live-fire exercise, North Korea first fired about 500 shells towards the South's waters near their disputed western sea border, known as the Northern Limit Line, according to the South's military.

More than 100 of them dropped in the south side of the NLL. In response, the South also launched a massive artillery barrage towards the North's waters.

Hagel stressed the U.S. has been clear that North Korea should halt provocative acts.

But he was noncommittal about whether the U.S. believes Pyongyang has entered a full-scale provocation cycle after months of a peace offensive.

He also avoided a direct answer when asked about North Korea's threat to conduct a "new type" of nuclear test.

The secretary only said the North Korea issue will be discussed when he visits China next week.

Meanwhile, he would not rule out the possibility that Scaparrotti may cancel his trip to Washington this week to testify before the House Armed Services Committee if the tensions in Korea do not let up.

Earlier in the day, the White House also described North Korea's act as "dangerous and provocative."

"We remain steadfast in our commitment (to) the defense of our allies and remain in close coordination with both the Republic of Korea and Japan," Jonathan Lalley, a spokesman for White House National Security Council, said in a statement.

The State Department characterized the North's latest act as a "deliberate decision" to further escalate tensions on the peninsula.

Marie Harf, the department's deputy spokeswoman, noted it followed North Korea's test-launches of a number of short-range and medium-range ballistic missiles and threats to carry out another nuclear test.

The communist nation should "desist from needlessly threatening regional peace and security," she said at a press briefing.

Pyongyang has a choice between continuing to escalate tensions and abiding by its commitments and obligations to rejoin the international community, said Harf.

"Unfortunately, what we've seen recently particularly is the former," she said. (Yonhap)