The United States and its allies are conducting a large naval exercise in the Black Sea and a separate anti-submarine drill in the North Atlantic Ocean, two regions where Russia has reportedly been holding war games of their own.

A total of 32 ships, 24 aircraft and 3,000 personnel from 19 countries are participating this year in Sea Breeze, an exercise co-hosted by the U.S. and Ukraine to improve teamwork in the Black Sea. Meanwhile, nine countries are taking part in NATO’s Dynamic Mongoose in the Norwegian Sea to practice anti-submarine warfare.

The two-week exercises in different parts of Europe are each in their final phases, but the overlap is a coincidence in scheduling by the separate commands, the Navy said.

Russian naval exercises in the Black Sea and Norwegian Sea are happening at roughly the same time as the allied exercises, continuing what has become a common practice by Moscow to mirror allied drills.

In the Norwegian Sea, Russia used two of its newest warships, the corvettes Boiky and Stoiky, to practice detecting and destroying enemy submarines, Norway’s The Barents Observer reported. Meanwhile, the Black Sea Fleet practiced interacting with reconnaissance planes and fighters to defend coastal areas against enemy navies, the Tass news agency reported.

The Norwegian Sea is about 425,000 square miles and the Black Sea totals about 168,000 square miles, so there is ample room for each exercise to operate. Russian surveillance of NATO exercises isn’t unusual and allies generally do not raise the issue unless they deem actions unsafe or outside the norms of international law.

The Russian navy is monitoring Sea Breeze but has done nothing to affect the exercise, a 6th Fleet spokesman said.

It’s unclear what Moscow thinks of Sea Breeze or Dynamic Mongoose, “but when NATO, a defensive alliance, conducts exercises, Moscow often interprets them as aggressive or nefarious,” said Michael Petersen, a Naval War College expert in Russia maritime studies.

Sea Breeze provides training on maritime interdiction, air defense, anti-submarine warfare, damage control, search and rescue, and amphibious operations.

“These areas of focus provide all participants with opportunities to increase their warfighting capability,” 6th Fleet commander Vice. Adm. Lisa Franchetti said in a statement. “In this era of great power competition, our naval forces are committed to the principle of credible deterrence.”

This year, almost all drills use scenarios that require participants to react quickly and improvise, Capt. Matthew Lehman, who’s leading the U.S. Navy contingent in the exercise, said in an email.

In the Norwegian Sea, Dynamic Mongoose is training allies to combine tactical skills to counter submarines. Russia has increased its undersea activity in the High North, U.S. officials have said.

Dynamic Mongoose is similar to the yearly anti-submarine Dynamic Manta drills held in the Mediterranean.

“Finding quiet submarines is a very challenging task that requires a high-end kit and sharp people,” Rear Adm. Andrew Lennon, commander of NATO submarines, said in an email. “Dynamic Mongoose not only lets our operators test their sonar skills but also allows larger groups of ships and aircraft to improve task group coordination.”

This is the second year that units trained north of the Arctic Circle. Next year the exercise will take place near Iceland, Lennon said.