Pakistan is poised to upgrade its air force by purchasing what are arguably the best combat aircraft already in use - Russian Su-35 fighters, and here is why.

A Pakistani government official spoke to IHS Jane's, confirming that the sides had already discussed a possible purchase of the advanced aircraft, as the Pakistani Air Force requires a two-engine fighter "that can fly for a longer range than the JF-17 and penetrate more deeply into the enemy's territory".

Currently the country's air force operates a fleet of US F-16s, French Mirage-5s, Chinese F-7s and Sino-Pakistani JF-17s.

Earlier, Moscow and Islamabad clinched a deal on the delivery of Mi-35M transport and attack helicopters to Pakistan, and the contract could be expanded.

While the media are discussing the PAK FA, F-35 and J-20, the fifth-generation aircraft being tested in Russia, the US and China respectively, the fully operational Su-35 seems even more reliable for the moment. It has been touted as "4++ generation using fifth-generation technology", rendering it superior to other fourth-generation fighters under development.

© Sputnik / Mikhail Voskresenskiy Su-34 (left), T-50 (centre) and Su-35 (right) aircraft at the 2015 MAKS air show's opening ceremony in the Moscow suburban town of Zhukovsky.

In fact, only the absence of stealth technology and an active electronically scanned array formally separates this plane, which is unbelievably maneuverable at low speeds, from the family of fifth-generation jets.

The Su-35, NATO reporting name Flanker-E, is a multirole fighter that is capable of engaging several air targets simultaneously.