Fighter planes of the Royal Canadian Air Force have arrived in Romania to begin their enhanced air policing mission this Sunday, according to NATO.

Six CF-18 Hornet planes and about 135 personnel of the Canadian Armed Forces Task Force-Romania received readiness certification in a ceremony Thursday at the Mikhail Kogainiceanu air base in southeastern Romania.

"NATO air policing is part of the principle of collective defense as a backbone for the alliance," Lt. Gen. Fernando de la Cruz Caravaca, commander of the Combined Air Operations Center at Torrejón Air Base in Spain, said in a statement.

"It provides 24/7 airspace safety and security over the member nations by uses air command and control, air surveillance and control systems, and quick reaction alert aircraft," he said.

The RCAF detachment, from 433 Tactical Fighter Squadron stationed in Bagotville, Quebec, will work with the Romanian Air Force under NATO command and control as part of Operation Reassurance, Canada's involvement in NATO assurance and deterrence measures.

It includes patrol of Romanian airspace and, if necessary, interception of any aircraft entering it without authorization, a statement on Thursday from the Canadian Armed Forces said.

Canadian aircraft will fly alongside Romanian Air Force F-16 Fighting Falcons and MiG-21 Lancers, and will participate in combined training on the Black Sea shore with NATO allies.

The deployment is expected to last until December and is the fifth time since 2014 that Canada has contributed to the NATO mission in Romania.

"Having deployed on this mission in 2014, I know how much our pilots and entire Task Force benefit from this opportunity to work with our NATO allies," said Lt. Col. David McLeod, commander of the Canadian Air Force Task Force-Romania.

"COVID-19 has not dulled the enthusiasm of the great team that comes with me and I know their knowledge and professionalism will be evident throughout the deployment," McLeod said. "Working alongside our NATO allies is critical to collective defense but also provides an invaluable opportunity to learn from one another."