UAE investigating U.S. pro-democracy group staffer DUBAI (Reuters) - United Arab Emirates authorities said on Friday they were investigating an employee of a U.S. pro-democracy group after briefly detaining him as he tried to leave the Gulf state. Slobodan Milic works for the National Democratic Institute which was last week ordered to close its UAE offices. The Serb was detained at Dubai airport on Thursday evening, questioned and then allowed to return to his apartment in Dubai, NDI said. A UAE official said Milic had been questioned about NDI's activities and the investigation was continuing. "We are waiting for the results of the investigation," the official said, when asked if Milic could leave the UAE. He did not elaborate about the nature of the probe. The UAE said on Thursday licensing irregularities were behind the closure of "some foreign institutions" in the Gulf state, a week after NDI and German democracy group Konrad-Adenauer-Stiftung (KAS) were told to shut their offices there. Western-allied UAE, cushioned by its huge oil wealth, has escaped the upheaval shaking much of the Arab world, but allows no political parties and keeps a wary eye on signs of political dissent. In Egypt, NDI was one of a number of civil society groups raided by police last year. Washington hinted at the time it could review its $1.3 billion in annual military aid to Cairo. That row was defused when Egypt lifted a travel ban it had placed on the groups' American staff, whom it accused of carrying out political activities unrelated to their work, failing to obtain proper licenses and receiving foreign funds without Cairo's approval. NDI is loosely affiliated with the U.S. Democratic party, while KAS has links with Chancellor Angela Merkel's Christian Democratic Union of Germany. Another NDI employee, Pat Davis, an American, flew out of the UAE on Thursday, said NDI regional director Les Campbell. Reporting by Isabel Coles; Editing by Rosalind Russell