Several sources have confirmed to USNI News that three powerful US carrier strike groups will participate in a joint exercise later this week off the Korean peninsula in the Sea of Japan. The move, which coincides with President Donald Trump’s ongoing Asia tour, is reportedly the first tri-carrier operation in this area in a decade.

The exact timing of the exercise, which is expected to last four days, wasn’t disclosed. USNI News says the carriers are the USS Ronald Reagan, USS Nimitz and USS Theodore Roosevelt, along with their supporting warships and air wings.

Officially, the Pentagon maintains that only two carriers will likely be involved in the joint operations near Korea. But US officials have acknowledged that there are currently three US carrier groups in the western Pacific.

“These three carriers are not there specifically targeting North Korea. … This is a routine demonstration of our commitment to the region,” Chairman of the Joint Chiefs of Staff Gen. Joseph Dunford said last week.

The convergence of the three ships in the Sea of Japan is only temporary. USNI News reports that the Nimitz is in transit to its homeport in Washington state, while the Roosevelt is set to start operations in the Persian Gulf since departing last month from San Diego. The Reagan, which is based in Japan, has been operating off the Korean peninsula since last month.