In January 1948, the Soviet Union issued a specification for a long-range, all-weather Interceptor, capable of intercepting hostile aircraft far from the attacker's targets by day and night.

The crew of two (aircraft commander and radar operator, who were provided with dual controls) sat on individual ejector seats in a side-by-side, unpressurised cockpit.

[4][7] The first prototype, designated R-1, was powered by two 22.25 kN (5,000 lbf) thrust Klimov RD-45Fs, unlicensed copies of the British Rolls-Royce Nene engine, and was armed with two Nudelman N-37 cannon, positioned on either side of the air intake.

[8] A second prototype, R-2, which differed in having more powerful (26.25 kN (5,900 lbf)) Klimov VK-1 engines, a third N-37 cannon and an improved windscreen and canopy followed in November 1949.

[4] The R-2 was badly damaged when a cannon shell exploded, and the aircraft was rebuilt, with the wings modified, adding a third fence, flying again as the R-03 on 30 March 1950.