Gunmen in Ukraine's autonomous Crimea region threatened a United Nations Middle East envoy, Robert Serry, forcing him to abort his visit to the disturbed region halfway, Wednesday.

Around 10 to 15 unidentified men confronted Serry, who was sent to evaluate the situation in Crimea, at gunpoint outside the Ukrainian naval headquarters in Simferopol, capital of the autonomous republic. The gunmen also threatened a journalist who witnessed the argument, reports The New York Times.

An assistant travelling with Serry told the Agence France-Presse that the men did not let the diplomat return to his vehicle. Serry then went to a nearby café to inform the mission about the incident. The activists also stopped his exit, the assistant said.

ITN reporter James Mates who was accompanying Robert Serry, tweeted saying: "He (Serry) refused to go with men blocking car, got out and walked until he found coffee shop. He's asked ITV News team to stay with him."

He was later escorted out of the place by the police. The mob of around 100 angry protestors were  even waving Russian flags, reports Reuters.

"He is in good shape physically. He is not kidnapped," Jan Eliasson, the United Nations deputy secretary general told the NY Times.

"He wants to fly to Kiev but there is no ticket for him yet. He is hoping that he can leave Crimea without further incident," Serry's assistant told AFP.

The authorities at the UN told AFP that Serry, a former Dutch ambassador to Kiev, was travelling with a UN colleague when the armed gunmen warned "he should leave Crimea."

Vadim Kastelli, Serry's interpreter, said the envoy was taken to Simferopol airport to board the next  flight out and amid the commotion did not get a chance to collect his luggage from his hotel room. Kastelli said Serry wanted to stay overnight to attend meetings with regional officials.

"Robert said all the things that are happening show how concerned he is and concerned all the people of the world should be about what is happening in Crimea," he said after Serry boarded the flight, reports Reuters.

Nikolai Rudkovsky, a Ukrainian member of parliament, said Serry, boarded a flight for Istanbul. Rudkovsky, who was at the Simferopol airport, said, "He (Serry) asked to me to tell you that his recommendation was that all sides sit down and look for an understanding."

Last week, West's focus shifted to Crimea after groups of unidentified armed men seized government and parliament buildings and took control of the two airports. Russian flags were raised over the captured buildings. Although the identity of the gunmen is unknown it is speculated that they were from the Black Sea Fleet of Russia.