The long awaited deal has taken place. A deposit has already been paid. Turkey has finally signed the $2.5bn (£1.9bn) contract with Russia to buy S-400 advanced missile defense system. With a range of 400 kilometers (248 miles), the system can shoot down up to 80 targets simultaneously, aiming two missiles at each one, at an altitude of up to 30 km.

The system is not operationally compatible with the systems used by NATO countries, which gives Turkey a military capacity independent of the alliance. NATO commanders will not have control over it. The identification friend or foe (IFF) equipment won’t prevent Turkey from using it against NATO aircraft and missiles. Reaching full operational capability will require Russian personnel to be stationed in Turkey on advice, assistance and training missions.

The technology transfer component of the S-400 deal is especially important as it would allow Turkey to rapidly expand domestic defense industry with Russia’s help. Russia would supply two batteries and help Ankara build two more such systems. A few years ago, the US refused to let Turkey produce Patriot air defense systems on its soil and the deal was off.

Ankara does not have industrial infrastructure to produce air defense systems. Russian specialists will have to come and build it from scratch. As a result, Russia will get access to the defense infrastructure of a NATO member state. The agreement to build the Akkuyu nuclear power plant in Turkey, which is to be launched by 2023, is another example of fruitful economic cooperation.

NATO insists members of the alliance are obligated to use military hardware that is interoperable with each other's systems. But the S-400 deal is not the first time the principle of interoperability is not observed. Greece purchased Russia's S-300 missile system several years ago.

The move – a further sign of Ankara's gradual estrangement from its Western allies – meets the strategic goal to acquire the nationally controlled defense capability. Turkey has also criticized the US and its allies for their reticence about selling it military arms and technology.

As had been expected, the deal triggered the anger of the United States and other NATO members. The US had long been warning Turkey against the deal. "We have relayed our concerns to Turkish officials regarding the potential purchase of the S-400. A NATO interoperable missile defense system remains the best option to defend Turkey from the full range of threats in its region," Pentagon spokesman Johnny Michael said in a statement.

Maryland Sen. Ben Cardin, the ranking Democrat on the Senate Foreign Relations Committee, asked the US administration to assess how the deal might affect Turkey’s NATO membership and US security assistance to Ankara, which includes weapons sales. He issued the warning on September 14 in a letter to Secretary of State Rex Tillerson and Treasury Secretary Steve Mnuchin. According to him, the deal violated a bill signed into law in August that imposes sanctions "on any person that conducts a significant transaction with the Russian Federation’s defense or intelligence sectors."

The idea of introducing sanctions against Turkey has been on the EU’s agenda for quite some time. The announcement of the deal with Russia came after German Foreign Minister Sigmar Gabriel said his country was suspending all major arms exports to Turkey because of the deteriorating human rights situation in the country and the increasingly strained ties. Gabriel added he believed that Turkey had also abandoned NATO’s common values. The idea of economic sanctions against Turkey is quite popular in Germany.

So, the three big powers, Russia, Turkey and Iran, united by the desire to end the bloodshed in Syria and rout terrorists, have become the targets of Western sanctions already imposed or still to be introduced. The pressure makes them get closer to each other. The cooperation between Russia and Turkey is on the rise and offers great prospects. Iran's Armed Forces Chief of Staff, Major General Mohammad Bagheri visited Turkey in mid-August – the first visit by an Iranian chief of staff since Iran’s 1979 Islamic revolution. The common threat of terrorism and Western pressure nudge Russia, Turkey and Iran towards one another.

The three states work together within the framework of Shanghai Cooperation Organization (SCO) where Russia is a full-fledged member, Turkey has the status of dialogue partner and Iran, an observer, is expected to become a member soon. Last November, Turkish President Recep Tayyip Erdogan said Turkey could become part of the SCO.

Ankara is also showing increasing interest in the Eurasian Economic Union (EAEU). It was invited to join the organization in 2014. This will open new opportunities for developing trade. Furthermore, many of the present and potential members of the EAEU are countries with whom Turkey already has close relations. The Eurasian Economic Union aims to finalize a free-trade deal with Iran by the end of the year. Reaching a deal with Iran on free trade would represent a notable victory for the organization. With Turkey and Iran as members, the EAEU would acquire a global dimension.

Obviously, there is one result the Western sanctions produce – the targeted countries come together to create alternative poles of power. Threats and restrictive measures spur the process. This policy has failed to keep Turkey away from military cooperation with Russia. In the multipolar world there is always an alternative to turn to.