U.S. moves to bolster NATO allies as Russia continues massing troops along Ukraine’s border

Russia continued funneling ground forces into Belarus and along its border with Ukraine over the weekend as U.S. officials engaged in “active discussions” with NATO allies about sending additional troops to shore up their defenses, Pentagon officials said.

The additional Russian troops pouring into the region include infantry, artillery and air defense units, officials said.

“These are combined arms capable forces,” chief Pentagon spokesman John Kirby told reporters on Monday. Russian President Vladimir Putin “has got a full range of military capabilities available to him, which only continue to increase the number of options available to him if he decides to move militarily.”

Moscow also is boosting its naval presence in the Mediterranean and the Atlantic. While they haven’t noticed any Russian naval activity that could be deemed “hostile,” U.S. intelligence officials are closely tracking the Russian vessels.

“They have put to sea more ships [and] they are exercising at sea,” Mr. Kirby said. “They are clearly increasing the capabilities they have at sea should they need it.”

The Pentagon already has notified about 8,500 troops to be prepared to deploy to Europe as the U.S. contingent of NATO’s 40,000-member Rapid Response Force.

Now the U.S. is considering sending additional military personnel to the region to reassure nervous NATO allies, especially new members near Russia.

Air Force Gen. Tod Wolters, who commands U.S. forces in Europe and is NATO’s supreme allied commander, could opt to shift personnel already based there to Poland and other NATO members threatened by Russia.

“We have tens of thousands of U.S. troops on European soil, both in a permanently based environment as well as on rotational orders,” Mr. Kirby said. “What we want to do is make sure that we’re providing options to the president and to our allies in case those options are needed.”