The Polish government held a ceremony attended by hundreds of local Poles to welcome the arrival of US troops on Saturday.

"The presence of American soldiers in Poland is another step in our strategy to ensure safety and security for Poland and the region," Polish Prime Minister Beata Szydlo told the troops in Zagan, a Polish town on the German border.

The deployment marks the first time Western forces are being deployed on a continuous basis to NATO's eastern flank.

"Today will go down in history," Szydlo said in a post from the Polish prime minister's office on Twitter.

The Polish Defense Ministry held "Safe Poland" picnics on Saturday in cities across the country to allow residents to meet with Polish and newly deployed US troops, view military hardware and eat traditional Polish army food.

A Zagan resident named Jan told news agency AFP that he wasn't certain that the US deployment was necessary, but said "it would be good if they scare the Russians a little, because they're out of control."

The 16th Sustainment Brigade of the US Army in Europe posted a picture on Twitter of Polish citizens posing for a photo with US troops and tanks.

The brigade includes some 3,500 US troops from Fort Carson, Colorado, and heavy equipment. The troops will also rotate through NATO partners Estonia, Latvia, Lithuania, Romania, Bulgaria and Hungary for exercises. A headquarters unit will be stationed in Germany and will be replaced after nine months.

The deployment comes in reaction to Russia's annexation of Crimea from Ukraine in 2014 and Moscow's backing of separatist insurgents in eastern Ukraine.

Russia has branded the operation a "threat" to its own security and interests and denounced the deployments.

Last summer, NATO leaders approved the troop rotation plans in Poland and the Baltic states to reassure them that they would not be left alone if Russia repeated its intervention in Ukraine.

rs/tj (AP, AFP)