RIO DE JANEIRO - Brazilian aircraft manufacturer Embraer Tuesday unveiled the first prototype of the largest self-made military transport plane.

Defense Minister Celso Amorim, Brazilian Air Force (FAB) commander Lt. Brigadier Gen. Juniti Saito and diplomats from 30 countries witnessed the unveiling of the KC-390 aircraft at the company's Gaviao Peixoto production hangar in the southeastern state of Sao Paulo.

"This significant milestone of the KC-390 Program demonstrates Embraer's ability to manage such a complex and high-technology project and to perform it on track," said Jackson Schneider, the company's president and CEO of defense and security.

The KC-390, to be used by FAB, is the result of a nearly 2 billion-US-dollar deal between Embraer and FAB in 2009 on the production of two types of military planes.

In May, FAB signed a 2.9 billion-dollar contract to purchase from Embraer 28 of the planes, which will eventually substitute the force's aging fleet of US-built Hercules C130s.

"The KC-390 will be the backbone of the FAB's air transportation network," Saito said.

The plane, designed mainly for transporting military troops and cargoes, can also be used in other types of missions, including aerial refueling, search and rescue operations, fighting forest fires, among others, the company said.

In addition to the FAB purchase contract, Embraer has tentative orders for another 32 KC-390s from other countries.

The plane will go into testing before a second prototype is built, with the first delivery of the aircraft due in early 2016.

Embraer is the world's third-largest manufacturer of commercial airplanes, after US giant Boeing and Europe's Airbus.