There are 100,000 U.S. troops in Europe as of Thursday, as NATO increases its presence in the eastern flank and Russia's invasion of Ukraine enters its fourth week.

In a press conference alongside Germany's minister of foreign affairs, NATO Secretary-General Jens Stoltenberg said the number of American soldiers in Europe has increased by several thousands in the last several weeks. 

Stoltenberg said NATO has increased its deterrence and defense, especially in the eastern part of the alliance, with hundreds of thousands of troops on "heightened alert." 

NATO SAYS ‘WE COULD HAVE DONE EVEN MORE’ IN LEAD UP TO RUSSIAN INVASION, BUT REJECTS NO-FLY-ZONE PLEAS 

There are now 40,000 troops under direct NATO command, Stoltenberg said. 

"This is our immediate response sending a clear message to Moscow that an attack on one ally will trigger a response from the whole alliance," he said. "Deterrence of defense is not about provoking a conflict but prevents a conflict. It’s about preserving peace." 

RUSSIA INVADES UKRAINE: LIVE UPDATES 

"I fully understand the devastation and desperation that President Zelenskyy and the Ukrainian people feel because they’re in an extremely difficult situation where they see civilian casualties, destruction every single day including attacks on hospitals, schools, civilian infrastructure," he added. 

NATO Secretary General Jens Stoltenberg addresses the media during a joint statement with German Chancellor Olaf Scholz prior to a meeting at the Chancellery in Berlin, Germany, Thursday, March 17, 2022. 

NATO Secretary General Jens Stoltenberg addresses the media during a joint statement with German Chancellor Olaf Scholz prior to a meeting at the Chancellery in Berlin, Germany, Thursday, March 17, 2022.  (AP Photo/Michael Sohn, Pool)

NATO has increased support to Ukraine through advanced weapon systems, air and missile defense, tank weapons, fuel and ammunition "critical for the Ukrainian force to mobilize against the invading Russian forces," he said. Since Russia annexed Crimea in 2014, NATO allies have trained tens of thousands of Ukrainian troops who are "now on the front lines fighting invading forces." 

CLICK HERE TO GET THE FOX NEWS APP

"The Ukrainian army’s defense forces is much bigger, much stronger, much better equipped, much better trained, much better commanded now than in 2014," he said. "The courage of the Ukrainian armed forces has enabled them to resist the Russian forces. Support we have been giving them for many years has proven to be extremely important, and therefore we continue to provide support to Ukraine." 

Stoltenberg provided the same 100,000 figure for U.S. troops in Europe and 40,000 troops under direct NATO command during a press conference Wednesday with U.S. Secretary of Defense Lloyd J. Austin III.