Two international rights groups are urging the United Arab Emirates to end crackdowns on perceived political opponents and release those in custody.

Monday's appeal by Amnesty International and Human Rights Watch follows the detentions of two people in the past week in the northern UAE emirate of Ras al-Khaimah, including a cousin of the emirate's ruler.

The rights organizations say UAE officials are holding at least seven other activists with links to an Islamist group that has been critical of some policies of the country's Western-allied leaders.

The UAE has stepped up pressures against calls for political reforms in the country, a federation of seven semiautonomous emirates that include Dubai and Abu Dhabi.