The Soviet agreement to export MiG-23MFs and MiG-25PDs to Syria was a major break-through: it was the time ever that the USSR showed readiness to deliver advanced weapons system de-facto equipped to the same standard as that used by its own military to a customer outside item Europe.
The Syrian Air Force, officially the Syrian Arab Air Force (SyAAF) is the air force branch of the Syrian Armed Forces and it was established in 1948.
In April 1974, Syria received the first two batches of MiG-23 fighter-bombers. Acquisition of additional aircraft from the USSR was stopped in 1975 due to differences of political nature between Damascus and Moscow.
In the late 1970s, an insurgency characterised by dozens of assassinations of government officials and military officers erupted in Syria. By 1978, the Moslem Brotherhood of Syria joined the armed uprising. Concerned by destabilisation of the government of President Hafez al-Assad, Moscow decided to restart providing arms and military aid. In April of the same year, a new arms deal was signed, including deliveries of advanced MiG-23MF and MiG-25PD interceptors.
As told by Tom Cooper & Sergio Santana in their book Lebanese Civil War Volume 1: Palestinian Diaspora, Syrian and Israeli Interventions, 1970-1978, although the aircraft delivered to Syria were second-hand, overhauled, former MiG-23Ms and MiG-25 of the VVS or PVO, the Soviet agreement to export MiG-23MFs and MiG-25PDs to Syria was a major break-through: it was the time ever that the USSR showed readiness to deliver advanced weapons system de-facto equipped to the same standard as that used by its own military to a customer outside item Europe.
The MiG-23MF was essentially the same the MiG-23M: although designated S-23E, its weapons system was the same as the S-23 on the original model, and primary armament consisted of the same R-23 MRAAMs operated by the Soviets. These could only be deployed against targets underway at altitudes above 1,000 metres (3,280ft), but had an effective engagement range of between 15km (8nm; for the IR variant, R-23T) and 25 kilometres (13.5nm; the SARH variant, R-23R, ASCC code AA-7A Apex-A). The centrepiece of the S-23E weapons system was the Sapfir-23D-III — an analogue, pulse radar. This utilised the — rather unreliable — ‘envelope detection’ technique to detect objects flying low over the ground: thanks to about 40 analogue filters ed to suppress ground clutter, it was capable of projecting only radar echoes from moving targets on the ASP-23D sight in the cockpit. Certainly enough, in a look-down mode, or a tail-chase type of engagement, the Sapfir-23D-III was extremely limited, having a detection range of barely 10-20 kilometres (5.3-10.6nm), respectively. It was already renowned as notoriously unreliable and its proper function was heavily dependent on constant fine-tuning of its AVM-23 analogue computer. Furthermore, it proved effective only over relatively flat terrain. However, by having a maximum detection range of about 45km (24nm) for fighter-sized targets at medium or high altitudes, in combination with R-23s, and if deployed with full support of a well-developed IADS — as already available in Syria — it was expected to prove at least a match for the Israeli F-15A/B Eagle, and superior to the Mirages and Kfirs. That said, conversion training of Syrian pilots and Soviet deliveries of MiG-23MFs advanced rather slowly: No. 67 Squadron was officially declared operational on this type only in May 1981.

The Syrians expected even more from the MiG-25PD. Manufactured for export purposes only, this variant entered production in 1978. It was equipped with the massive, I-band, Smerch-A2 radar low PRF pulse radar, with a transmission power of an enormous 600KW, modified through the addition of an anti-jamming capability in the form of the ‘azimuth only’ mode. This system used an inverse cassegrain antenna capable of sweeping +/-30 degrees to the side and ‘looking up’ for up to 14 degrees in elevation, and had a maximum detection range for bomber-sized target of 100km (54nm), with the ability to track and engage from a range of 60km (32nm). However, contrary to the fire-control system of the F-15A delivered to Israel in 1976, the Smerch-A2 lacked the look-down capability unless the aircraft was underway at or near its top operational ceiling. For this purpose the MiG-25PD was equipped with the same IRST as the MiG-23MF, though officially designated the 26Sh-1 installed in housing under the chin. Interceptor variants of the Foxbat were equipped with slightly improved (in comparison to their original variants) R-40RD (semi-active radar homing and R-40TD (infra-red homing) air-to-air missiles (ASCC NATO-codename `AA-6 Acrid’), of which it could carry four — two under each wing. Although the biggest air-to-ai missiles in world-wide service of the early 1970s, these had a maximum engagement range of only 50km (27nm): what did matter about the R-40s was their large, 70kg (154lbs) blast-fragmentation warhead. Because the R-40s could only sustain about 2.5gs, the MiG-25PDs were modified to carry up to four R-60M or R-60MK missiles instead of the outer pair of Acrids: however, although capable of tracking targets manoeuvring at up to 9gs, these were short-range weapons only. As far as is known, between 1979 and 1982, Syria received a total of 46 MiG-25s, of which 10 were MiG-25RBs. The latter was a dedicated reconnaissance variant, equipped with reconnaissance cameras and a relatively primitive ELINT-system. At least two of these were reportedly equipped to the MiG-25RBS standard, which included the Shompol side-borne looking radar (SLAR), but it remains unknown if these arrived before or after 1982: indeed, for all practical purposes, the Syrian fleet of Foxbats was still not operational as of that year.
Lebanese Civil War Volume 1: Palestinian Diaspora, Syrian and Israeli Interventions, 1970-1978 is published by Helion & Company and is available to order here.

Additional source: Wikipedia
Photo credit: U.S. Air Force and Israeli Air Force
So where are all there MIGs now 😂