NATO leaders slated to bolster troop presence in Bulgaria, Hungary, Romania and Slovakia

NATO Secretary-General Jens Stoltenberg said Wednesday the alliance is likely to bolster troops along the alliance's eastern flank, deploying four new battle groups in Bulgaria, Hungary, Romania, Slovakia.

"I expect leaders will agree to strengthen NATO's posture in all domains, with major increases in the eastern part of the alliance on land, in the air and at sea," Stoltenberg said during a press conference ahead of the NATO leaders summit in Brussels.

Currently, the United States has deployed more than 100,000 servicemembers alongside NATO's 40,000 troops.