Four British Royal Air Force Typhoon fighter jets landed in Siauliai airbase in northern Lithuania on Monday, the first of 12 fighters that will boost air patrols in the Baltics, and 150 US troops were deployed to the Amari air base in Estonia.

According to Reuters, the three Baltic states of Estonia, Latvia and Lithuania have small military forces and have been warily watching Russia reasserting itself in its former dominions.

A total of 600 US troops have now been deployed to Poland and the Baltics for infantry exercises, where they are expected to remain on rotation until the end of the year.

"Clearly we are here to reassure our Baltic allies that we are able to protect their airspace, should it be needed," RAF commanding officer Simon Hulme told reporters in Siauliai, standing in front one of the Typhoons.

Siauliai airport, a major military base in Soviet times, lacks modern infrastructure, so the UK squadron will be housed in temporary hangars built on the tarmac. Mission headquarters are housed in a block of metal containers clustered nearby.

Two of the four hangars were half-completed on Monday.

The Baltic states have been members of NATO since 2004, but foreign troops have not had a permanent presence before, partly to avoid antagonizing Russia.

NATO prepared plans for a defense if the Baltic region first in 2010, after Russia invaded Georgia, according to US diplomatic cables leaked by the whistle-blowing website Wikileaks.

BA/BA