State and airports authority officials have reached an agreement with two contractors to construct the first leg of the Dulles Corridor Metrorail Project, a project now expected to cost as much as $2.7 billion.

Project officials on Friday announced the end of negotiations with Bechtel Infrastructure and Washington Group International, who together make up Dulles Transit Partners, to design and build the rail extension’s initial phase from west Falls Church to Wiehle Avenue, near Reston.