MOSCOW — Chinese and Russian warships practiced together in the Baltic Sea on Tuesday, in the first joint naval exercise the two countries have held in the area, which has been a focus of heightened tensions between Russia and the West.

All sides appeared eager to avoid inflaming the tensions. The NATO alliance, which has six member nations on the Baltic, noted matter-of-factly that the naval drills were being monitored “as a matter of routine.” Chinese and Russian commanders insisted that the exercises were not aimed at any third country.

China and Russia have been holding joint military exercises for more than a decade; they started holding joint naval drills in 2012. The countries see their budding military partnership as a way to show that they do not stand alone, despite efforts by the West to isolate them over various disputes.

NATO, which has repeatedly complained in the past about snap Russian military exercises that were not announced in advance, said on Tuesday that it had been aware of plans for the Russo-Chinese naval maneuvers, called Joint Sea 2017, for several weeks. The alliance said it arranged for allied navies to greet the Chinese vessels last week as they headed for the Baltic Sea.