Three Danish lawmakers say Nauru has blocked them from taking part in a visit to a detention center where Australia sends asylum-seekers.

Johanne Schmidt-Nielsen, Jacob Mark and Naser Khader were scheduled to go on a two-day visit to the Pacific island nation of Nauru with other members of the Danish Parliament's Immigration Committee.

Schmidt-Nielsen suggested Tuesday on Facebook that she and Mark were blocked because they are left-wing lawmakers who have criticized Australia's offshore asylum detention policy. She said it's anyone's guess why Khader, "without having criticized Nauru or Australia," was also excluded.

Khader, a conservative politician originally from Syria, wrote in a separate Facebook post that he had no idea why he was blocked and "hope it doesn't have anything to do with my name and place of birth."