Amnesty International says one of its researchers was denied entry to the United Arab Emirates, where he was planning to speak about companies' responsibility in ensuring the rights of migrant laborers in the Gulf.

The London-based group said Wednesday that acting head of business and human rights James Lynch was stopped upon arrival to Dubai late the previous night and given no explanation for the refusal. It says a deportation order mentioned security concerns.

Emirati officials had no immediate comment.

The Emirates is sensitive to criticism about conditions for millions of migrant workers employed in its booming construction industry.

Amnesty says the country previously denied entry to its staff and that of Human Rights Watch, as well as New York University professor and labor rights researcher Andrew Ross.