A US Navy helicopter crashed onto the flight deck of an aircraft carrier in the Philippine Sea on Friday, injuring 12 personnel on board, according to two US Navy officials familiar with the incident.

The MH-60 Seahawk hit the flight deck of the USS Ronald Reagan shortly after takeoff around 9 a.m., according to a statement released by the Navy’s Seventh Fleet.

Four people were hurt on the helicopter and eight were injured on board the ship, according to the officials. All personnel who were hurt are in stable condition and are being evaluated by medical staff.

The official said injuries ranged from minor lacerations to fractures, and that two sailors had been “seriously injured.”

Some personnel were evacuated to medical facilities in the Philippines, the same official said.

An investigation has been opened into the cause of the crash, according to the statement.

The incident occurred during routine operations in the Philippine Sea, which spreads north and east of the Philippines.

The aircraft carrier “remains fully mission capable” and normal flight operations to support the mission of “support and security and stability in the Indo-Pacific Region” have resumed, the Navy said.

Last week the Nimitz-class, nuclear-powered aircraft participated in the International Fleet Review near South Korea’s Jeju Island.

In May 2017, the USS Ronald Reagan began sea trials in the Pacific before replacing the USS Carl Vinson near the Korean Peninsula.

The 1,092-foot Reagan carries a crew of 4,539 and is equipped with roughly 60 aircraft, according to the Navy. It was commissioned in 2003 and cost about $8.5 billion.