Poland welcomes 3,500 US troops amid fears over Russia aggressionPl

Poland has welcomed US troops into the country amid security fears over Russia - with joint picnics held for citizens and American soldiers.

The arrival of the 3,500 soldiers is part of a deployment to NATO's eastern flank aimed at deterring aggression from Moscow.

Hailing from Fort Carson, Colorado, the so-called "Iron Brigade" is made up of highly trained soldiers and heavy military equipment.

They will be deployed with NATO partners Estonia, Latvia, Lithuania, Romania, Bulgaria and Hungary on a rotational basis.

Prime Minister Beata Szydlo welcomed the troops in Zagan, the Polish town on the German border where the brigade will be headquartered.

"We hope you feel at home," she said.

"The presence of American soldiers in Poland is another step in our strategy to ensure safety and security for Poland and the region," she added.

The defence ministry held "Safe Poland" picnics on Saturday in cities across the country.

The picnics enabled people to meet Polish and US troops and view their military hardware. They were offered typical Polish army food, including pea soup with ham.