Sweden. The Swedish air defense failed to respond. Two Tu-22Ms flew supersonic over the Baltic Sea on 24 March 2015. Two Tu-22Ms approached Öland in international airspace on 21 May 2015. The Swedish Air Force sent two Saab JAS 39 Gripen fighters to mark their presence. On 4 July 2015, two Tu-22Ms approached the Swedish island of Gotland without violating its airspace, followed by Swedish and other fighter aircraft. In 2014, Russian aerospace expert Piotr Butowski estimated there were seven squadrons of Tu-22Ms in service, each with approximately 10 aircraft, stationed at three airbases; 40 at Belaya airbase in southeastern Siberia, 28 at Shaykovka airbase southwest of Moscow, and 10 at Dyagilevo airbase in Ryazan southeast of Moscow which serves as the training unit for the bomber. With the removal of the aircraft's in-flight refueling capability due to the START I treaty, the Tu-22M's internal fuel capacity limits its operational range (combat radius unrefueled: 4,000–5,000 km (DIA), 3,360–3,960 km (CIA) estimate) from its home bases to only around Russia's immediate sphere of influence. Syrian Civil War On 17 November 2015, as part of the Russian military intervention in the Syrian Civil War, Russia used 12 Tu-22M3 bombers to hit targets in Syria, along with cruise missiles fired from the Mediterranean and Tu-95 and Tu-160 strategic bombers. 22–31 January 2016, Tu-22M3s reportedly conducted 42 sorties performing airstrikes in the vicinity of Deir ez-Zor. On the morning of 12 July 2016, six Tu-22M3 bombers carried out a concentrated attack using high-explosive ammunition on Daesh targets east of Palmyra, Al-Sukhnah and Arak. On 14 July, six Tu-22M3 bombers having taken off from their base airfields in Russia delivered another massive strike on the newly detected IS facilities in the areas east of Palmyra, as well as in Al-Sukhnah, Arak and the T-3 oil pumping station in the province of Homs. New raids were conducted on 21 July, 8 August, 11 August, 14 August 2016. On 16 August 2016, the bombers began to fly missions in Syria using Iran's Hamedan Airbase. Since late January 2017, six Tu-22M3s resumed airstrikes in the area of Deir ez-Zor to prevent capture of the city by jihadists and again in late 2017 to support a government offensive. In May 2021, three Tu-22Ms were temporarily deployed to the Khmeymim airbase in Syria. Tu-22Ms were again deployed in eastern Mediterranean in June of the same year for large RF Navy