The United States and European Union have asked Zimbabwean authorities to investigate the disappearance of a journalist-turned-activist who has been staging sit-ins in the capital demanding that President Robert Mugabe resign.
Itai Dzamara was on Monday forcibly taken by five unidentified men and bundled into an unmarked truck near his home in the capital, Harare, according to his family.
Dzamara and a handful of colleagues are demanding Mugabe's resignation on the ground that he has mismanaged the economy.
In October, Dzamara was arrested after delivering a petition at Mugabe's offices calling on the 91-year-old leader to resign and pave the way for fresh elections.
The EU and U.S. said in separate statements that they were concerned about Dzamara's abduction and disappearance.
"If he is being held in state custody, it is vital that his fundamental human rights and freedoms as guaranteed by Zimbabwe's constitution be honored," the U.S. Embassy said.
The EU said the government should "take all necessary measures to ascertain Mr, Dzamara's whereabouts, safeguard his well-being and accord him the full protection of the law."
The Zimbabwe Lawyers for Human Rights on Tuesday filed an application at the High Court in which it accused state security agents of abducting Dzamara and asked for his release.
Vice President Emmerson Mnangagwa told parliament that Dzamara was not being held by the state and that law enforcement agencies were searching for him.
State security agents in Zimbabwe have in the past abducted activists opposed to Mugabe's rule and later turned them over to the police. Some of the activists have alleged being tortured, claims that the government has denied.