MUNICH  Romania’s top defense body approved an American proposal to base missile interceptors there, the country’s president said Thursday in a hastily arranged announcement.

The president, Traian Basescu, said in a statement that Romania, a former Warsaw Pact member and now part of NATO, was prepared to negotiate with the United States to accept ground-based interceptors as part of an antiballistic missile defense system. He said it could be working by 2015.

While the participation of Poland and the Czech Republic in the missile shield had been well known, the possibility that Romania would join them was not.

Romania made its announcement as Defense Secretary Robert M. Gates was in Turkey for a NATO meeting. He was not immediately available to comment but the White House spokesman, Robert Gibbs, said the announcement was welcomed. “We’re pleased that Romania has agreed to participate in that defense shield,” he told reporters in Washington.