JUBA, South Sudan — Rebel leader Riek Machar returned to the South Sudan capital, Juba, on Tuesday to become vice president and to try to end the civil war that in 2½ years has killed tens of thousands of people and forced more than 2 million from their homes.

After landing at Juba International Airport, where doves were released and a welcoming crowd ululated, Machar briefly addressed the press before driving to the presidential palace to be sworn in as first vice president to President Salva Kiir, according to a peace deal signed eight months ago under intense international pressure.

‘‘I’m happy to be back,’’ Machar told reporters at the airport. ‘‘The war was vicious. We have lost a lot of people in it and we need to bring our people together so that they can unite, reconcile, heal the wounds, the mental wounds that they have.’’

The August peace deal calls for a two-year transitional government of ministers and parliamentarians from the two sides before new elections.

Machar’s return is one of the biggest steps toward realizing the peace deal meant to end the fighting, but should not be met with ‘‘huge optimism,’’ cautioned Jacob Chol, dean of Juba University’s political science department.

At the United Nations, the Security Council welcomed Machar’s return and swearing-in and strongly urged both leaders to quickly form the transitional government, fully implement the peace agreement, respect human rights, and deal with the ‘‘dire humanitarian situation.’’

Sudan’s deputy UN ambassador, Joseph Moum Malok, told the council the national unity government will be formed ‘‘in a day or two.’’

Associated Press