Foreign trekkers have been robbed at gunpoint in a number of incidents in eastern Nepal.
The trekkers, thought to be British, German and Dutch, were in the remote districts of Taplejung and Panchathar, and were unharmed.
Targeting tourists is rare in the kingdom, where troops and Maoist rebels are fighting a bitter civil war.
The identity of the gunmen is not known, but the authorities say they suspect the rebels.
Although the Maoists say they never target tourists, there have been reports of extortion.
The area in which the incidents took place is a popular destination with Western trekkers, and at least two days walk from the nearest town.