The Associated Press interviewed NATO Supreme Allied Commander in Europe and US Air Force General Philip Breedlove about troop involvement in Eastern Europe. He said it is a possibility troops from any country, including the US, could be deployed to countries that feel threatened by Russia.

“Essentially what we are looking at is a package of land, air and maritime measures that would build assurance for our easternmost allies,” Breedlove told the AP. “I’m tasked to deliver this by next week. I fully intend to deliver it early.”

Asked again if American soldiers might be sent to NATO’s front-line states closest to Russia, the four-star U.S. general said, “I would not write off contributions from any nation.”

President Obama and Secretary of State John Kerry said many times that the US would not send troops to Ukraine, but promised NATO allies they would help with security. Vice President Joe Biden met with leaders of Poland, Lithuania, Estonia, and Latvia after Russian President Vladimir Putin officially annexed Crimea from Ukraine on March 21. Biden told the NATO countries the US will be there if Russia invades.

Russia claimed they “helped” Crimea to protect the ethnic Russians and Russian-speakers who live in the peninsula. On March 9, Latvia authorities feared they were Putin’s next target after the Russian ambassador to the country said Moscow is ready to provide Russian citizenship for the ethnic Russians in Latvia. A week later, a Russian diplomat told the United Nations Human Rights Council Moscow is concerned over the treatment of Russian speakers in Estonia, which made the country fear Putin will also target them.

NATO is also alarmed over the Russian troops on the Ukraine border. Ukraine is not a NATO country, but does border the Baltic states and Poland. Breedlove said there are about 40,000 Russian troops and satellite photos show they are at the ready position. The troops have engaged in military exercises, but Moscow said it was to familiarize the soldiers with unfamiliar lands.

The US provided more military equipment to Poland and NATO sent in more air patrols to the Baltics. Breedlove is ready to do more if necessary.