An Emirati official said that the 65-year-old former teacher had been detained because his residence permit had expired.
Abdurrahman Abu Zaid is in detention "because he violated residency rules" and he is "free to go to any country of his choice," the official told AFP, requesting anonymity.
In a May 29 statement posted on its website, London-based Amnesty charged that UAE authorities were "planning to forcibly return" Abu Zaid, who is "understood to be a member of the outlawed Syrian Muslim Brotherhood," to Syria, "where he would be at risk of torture."
It said Abu Zaid, who has lived in the UAE since 1976, "was arrested in early May and moved to the central prison in Dubai on 21 May, apparently in preparation for forcibly returning him to Syria."
Amnesty called for appeals to be sent to UAE officials to urge them not to force Abu Zaid to return to Syria, where there are "thousands of political prisoners" and "torture is widespread."
The Emirati official said Abu Zaid had lived in the UAE under the sponsorship of the education ministry but his contract was terminated five years ago, leading to loss of residency.
The issue has "no political implications," the official said.
On Tuesday, Syrian President Bashar al-Assad ended a three-day visit to the UAE.
Syria suppressed a deadly uprising by the Muslim Brotherhood in the 1980s and membership of the organisation remains outlawed on pain of death, although death sentences have invariably been commuted to prison terms in recent years.
