Russian warplanes In Syria

Russian President Vladimir Putin recently signed a deal with the Syrian regime of Bashar al-Assad to maintain Russia's access to a Syrian air base for the next 49 years. While Russia says it will use the base to fight terrorists, it has been widely condemned for targeting civilians in the war-torn nation.

Here's a look at the warplanes that Russia has sent to Syria since ramping up its military involvement in 2015.

Meet the Tupolev Tu-160M

Affectionately called the White Swan by Russian airmen, the Tu-160 is the final strategic bomber designed for the Soviet Union.

It made its first flight in 1981. A modernized version, with improved electronics and avionics, the Tu-160M, took to the skies in December 2014.

Putin poses in a Tu-160

Russian President Vladimir Putin poses inside a Tu-160 before taking a supersonic flight in 2005. With a top speed of Mach 2.05 (1,573 mph), it's the fastest bomber currently in use.

The White Swan flies over Red Square

The Tu-160 bomber, or "Blackjack" as it's called by NATO, has a crew of four (pilot, co-pilot, bombardier, defensive systems officer) and can carry up to 88,200 pounds of ordnance.

Here, a Tu-160 flies over Moscow's Red Square during a 2015 Victory Day parade.

Russia's White Swan

Russia has made no secret about its use of the Tu-160M strategic bomber against Syrian rebels.

Notably, during a 2015 run, one of the Russian bombers flew near British airspace in what The Telegraph reported as a show of strength.

Su-35: The top Russian air-superiority fighter

The Sukhoi Su-35 is a twin-engine, super-maneuverable, multirole fighter that seats one. National Interest's defense editor Dave Majumdar called it the "top Russian air-superiority fighter in service today."

Su-35: A modernized warplane

Making its first flight in 2008, the Su-35S is an upgraded version of Russia's Su-27. It was given the name "Flanker-T" by NATO.

Syria's Assad inspects an Su-35

According to Russia's Rossiyskaya Gazeta, the government's daily newspaper of record, four Su-35 planes were sent to the Khmeimim Air Base in Syria for combat missions in January 2016.

On June 27, 2017, Syrian President Bashar al-Assad tweeted this photo of the leader inspecting a Russian Su-35 at Khmeimim.

Su-35: The underside

The Su-35 can reach a top speed of Mach 2.25 (1,726 mph) at altitude. It carries up to 17,600 pounds of ordnance.

Meet the Sukhoi Su-30

The Sukhoi Su-30, nicknamed "Flanker-C" by NATO, is is a twin-engine, super-maneuverable, multirole Russian fighter that seats two. It is most similar to the U.S. F-15E Strike Eagle.

Su-30: A mid-air refueling

Su-30 planes have a range of 1,860 miles at altitude. This can be extended much further with the use of mid-air refueling via a Russian II-78 plane.

Prepping the Su-30 for battle

Servicemen prepare a Sukhoi Su-30SM fighter jet at a Russian military base in northwest Syria in December 2015.

The planes conducted air strikes against a range of anti-regime armed groups, including U.S.-backed rebels and jihadist groups.

Su-30: The underside

Each Su-30 has 12 external hardpoints for carrying up to 17,600 pounds of armaments. It can fly at speeds of Mach 2 (1,535 mph) at altitude.

India's Su-30MKI

Russia doesn't just manufacture planes for its own military. India has purchased 230 Su-30MKI variants from Russia (one of which is seen here).

China has been another major purchaser of Su-30 fighters.

Su-25SM: The most effective Russian plane in Syria

Called the "single most effective Russian aircraft deployed to Syria" by National Interest foreign policy magazine, the Su-25SM is a single-seat, twin-engine attack plane designed to provide close air support.

Here a Russian Air Force Su-25 SM attack plane takes off from a Syrian airfield in 2015.

Su-25SM: A proven workhorse

Andrew Galkin, commander of Russia's Southern Military District, detailed his country's use of Su-25SM attack planes to Russian news agency TASS.

Over a six month period in 2015-6, the planes "dropped about 6,000 bombs on the terrorists," he said.

Su-25SM: Powerful, but slow

The Su-25SM can carry up to 9,700 pounds of ordnance, but it's not very fast. Its top speed is Mach 0.79 (606 mph), making it about as speedy as a commercial airliner.

Su-25: Decades of service

The Su-25, known as "Frogfoot" by NATO, made its first test flight in 1975. Russia will continue upgrading the planes to Su-25SMs through 2020 to provide better attack precision and navigation, as well as the ability to launch newer air-to-air missiles.

Meet the Su-24

The Sukhoi Su-24, codenamed "Fencer" by NATO, is a supersonic, twin-engine, all-weather attack aircraft. It carries a crew of two: the pilot and a weapons system operator.

Su-24: Checking the weapons

The Su-24 has 8 hardpoints capable of holding up to 17,600 pounds of air-to-air and air-to-surface missiles. Its main weapon, however, is a 23 mm rotary cannon with 500 rounds.

Su-24: Preparing for a mission in Syria

Russian servicemen prepare one of 12 Su-24 fighter jets in northwest Syria in 2016. 

Su-24M2: An update of a 50-year-old design

Though the original plane design dates back to 1967 (T-6), the Su-24 has received a number of high-tech upgrades. The cockpit has been outfitted with multi-function displays and helmet-mounted sights, and can carry the latest guided weapons.