The United States will send “strategic” military assets to South Korea on a more regular basis to better deter North Korea, the South’s national security adviser said Thursday.

The decision, which has not yet been confirmed by the Pentagon, comes at a time of escalating tensions between the United States and North Korea, with many analysts concerned that the incendiary rhetoric, combined with more frequent flyovers by American bombers, could lead to a catastrophic miscalculation.

Chung Eui-young, national security adviser to President Moon Jae-in, told lawmakers in Seoul that American “strategic assets” could be deployed to South Korea on a “rotational” basis before the end of the year.

“This will help us expand our defense capabilities,” he told the lawmakers, according to Park Wan-joo, spokesman of the ruling Democratic Party.

He did not define “strategic assets” but South Korean officials usually define this as B-52 bombers, stealth warplanes, nuclear-powered submarines and aircraft carriers.

North Korea’s foreign minister recently threatened that his country’s military was ready to shoot down American military planes whether or not they were in North Korean airspace.

South Korean lawmakers were told that Washington had put its pledge on the deployment in writing, confirmed Park.

A spokesman for the United States Pacific Command, based in Hawaii, did not immediately respond to a request for confirmation or comment.

To celebrate its armed forces day, which falls on Sunday, South Korea’s military showed off some of its new weapons during a parade Thursday. For the first time, the military displayed its Hyunmoo ballistic missiles, which have all of North Korea within range and are a key element of its “Kill Chain” pre-emptive strike system.

“Our government’s determination to protect peace requires strong defense capabilities, and we will stand up against reckless provocations with strong punishment,” Moon said after inspecting the weapons.

“Securing counter capabilities against North Korean nuclear and missile threats is the most urgent task. We must further strengthen our Kill Chain and Korean missile defense system,” the president said.

South Korean Defense Minister Song Young-moo last month asked his American counterpart, Jim Mattis, to send such military hardware to the southern half of the peninsula on a regular basis.

A poll that YTN, a cable news channel, commissioned in August found that 68 percent of respondents said they supported bringing tactical nuclear weapons back to South Korea.

This issue has become more and more important to South Korea as tensions with North Korea have risen. With top Trump administration officials repeatedly saying that military options for dealing with Kim Jong Un’s regime are on the table, some in South Korea have become increasingly concerned about becoming collateral damage.

North Korea has enough conventional artillery trained on the greater Seoul area, home to 25 million people as well as several large American military bases, to cause widespread devastation before the American and South Korean militaries can respond.

If North Korea were to start unleashing its artillery on the South, it would be able to fire about 4,000 rounds an hour, Roger Cavazos of the Nautilus Institute estimated in a 2012 study. There would be 2,811 fatalities in the initial volley and 64,000 people could be killed that first day, the majority of them in the first three hours, he wrote.

As North Korea has continued to show off its growing arsenal — detonating a hydrogen bomb and firing increasingly-long range missiles — the U.S. and South Korean militaries have been conducting drills as a “show of strength.”

Air Force B-1B bombers from Andersen Air Force base in Guam and Marine Corps F-35B fighters from Iwakuni, Japan, have been dropping bombs on a training range in South Korea, just a few dozen miles from border with the North.

South Korean F-15K fighters have been doing the same, and South Korea has tested missiles designed to show that North Korea’s nuclear and missile test sites are within range.

But South Korean officials have been pushing for more than just flyovers from warplanes based in Japan or Guam: they want them to land in South Korea to show greater commitment to the military alliance.

But there are logistical reasons why that can’t happen, Jon Wolfsthal, a nuclear expert who served on President Barack Obama’s National Security Council, has said. Military airstrips in South Korea are not long enough for big, heavy B-52s, plus, the United States does not want its high-tech fighter jets sitting within North Korean artillery range, he said.

The U.S. regularly sends aircraft carriers to South Korea during their annual joint military exercises, as well as Los Angeles-class submarines. But the South Koreans are seeking a more consistent and higher-power show of American military commitment.