Indonesia is expected to sign a contract to purchase around a dozen Russian Sukhoi Su-35 fighter jets in a month's time.
These will replace its ageing Northrop F-5 fighters, and supplement a fleet of 16 Sukhoi Su-27 and Su-30 fighters that form the backbone of its air force, the sources were quoted as saying by Reuters at the Singapore Airshow today.
Indonesian companies will get contracts to manufacture some components for the Su-35, and the Russians are expected to set up a maintenance centre for the fighter jet in the country, added the sources.
However, the confirmation has not come from the Russian side yet.
If confirmed, this will be the second export order for Russia's newest fighter jet, with China inking a deal for 24 planes worth more than $2 billion in November 2015.
Indonesia also has around 12 early-model Lockheed Martin F-16s, and is receiving 24 refurbished F-16s from the United States as part of a 2011 government-to-government agreement.
It has also agreed to help fund South Korea's KF-X fighter jet programme, which hopes to develop a modern multi-role jet fighter in the 2020s. Jakarta expects to eventually get around 80 new fighter jets via this programme.