A group of protesters clashed with police on Monday as Dutch troops arrived in the NATO airbase at Incirlik in Turkey, in the south-east.
25 arrests were made as the protesters tried to breach the security perimeter. The Dutch are part of a 1000-strong contingent including US and German soldiers who have been sent to man missile batteries, strengthening Turkey's border with Syria.
German PAC-3 surface-to-air missiles also arrived on Monday at the nearby port of Iskenderun, to be greeted in their turn by demonstrations. Six Patriot batteries will be deployed; two each from the Netherlands, Germany and the US, at Turkey's request.
Turkey demanded NATO assistance in December, after a series of border incidents involving Syrian planes, and artillery shells falling on Turkish soil. At one point there were also concerns that Syria might fire chemical weapons close to the border.