NATO allies are putting their forces on alert and sending more ships and jets to locations in Eastern Europe, strengthening deterrence and defense as Russia continues to build up its military forces in and around Ukraine. The Alliance said in a press release issued Monday. 

"I welcome allies providing additional NATO forces. NATO will continue to take all necessary measures to protect and defend all allies, including by reinforcing the eastern part of the Alliance. We will always respond to any deterioration in our security environment, including by strengthening our collective defense," said NATO Secretary General Jens Stoltenberg.

A number of allies have reportedly made statements in recent days about the current or impending deployment of additional ones.

For example, Denmark is sending a frigate to the Baltic Sea and is going to send four F-16 fighter jets to Lithuania to support NATO's air defense mission in the region.

Spain is sending ships to join the NATO naval force, and is considering sending fighters to Bulgaria. France has expressed willingness to send forces to Romania under NATO command.

The Netherlands has been sending two F-35 fighter jets to Bulgaria since April to support NATO air policing activities in the region, and is also putting ship and ground units on standby for the NATO Response Force. The United States has also signaled that it is considering increasing its military presence in the eastern part of the Alliance.