LIELVARDE, Latvia (Reuters) - About 20 U.S. Apache military attack helicopters landed at Lielvarde military airfield in Latvia on Thursday, hours after Russian forces invaded Ukraine.

       The arrival of the choppers was first announced last week, when it was billed as a participation to the bi-annual international U.S.-led exercise Saber Strike.

       But on Thursday the Lithuanian defence minister was describing them as part of U.S. military reinforcements to the Baltic region after the Russian invasion of Ukraine.

       Some forty U.S. service members arrived in Latvia from Italy earlier on Thursday, the first group of what is expected to be a deployment of more than 300 troops, the Latvian Defense Ministry said.

       (Reporting by Janis Laizans in Lielvarde; writing by Andrius Sytas in Vilnius; editing by Niklas Pollard)