A Russian Navy ship, the Tsesar Kunikov, passed through the Bosporus with soldiers armed with Man-Portable Air-Defense Systems (MANPADS) on the deck on Friday , escorted by Coast Guard boats. The footage of armed Russian soldiers raised concerns in the Turkish public and is seen as Russia's latest attempt to provoke relations, while Turkey tries to de-escalate tension after the downing of a Russian jet that violated its airspace.Foreign Minister Mevlüt Çavuşoğlu said on Sunday that having Russian sailors equipped with shoulder-fired surface-air-missiles during Russia's warship transits on Dec. 4 was a "provocation" and that he hopes a similar incident won't happen again.Foreign Minister Çavuşoğlu defined this action as "provocative" and a "harassment." He told reporters that there are certain rules when a ship passes through Turkish straits and every ship – whether it is Russian or any other nationality – has to abide by them."If Turkey perceives any ship's transit as a threat, it will take the necessary action. A Russian soldier showing off a missile or a similar munition system while passing [through the Bosporus Strait] on a Russian warship is a provocation. We hope this incident is a one-time event, because it is not the right approach."Last week, Russia prohibited the import of Turkish food and banned chartered flights between the two countries. While Turkey is looking for economic options with which to retaliate, the seizure of five Turkish merchant vessels in Novorossiysk port on Friday brought tension to a new dimension. In response to the Russians' actions, four Russian ships were blocked in the Black Sea port of Samsun for hours on Saturday. Moreover, if the Russian side escalates the tension, Turkish officials are considering obstructing Russian ships in the Bosporus and Dardanelles straits.Passage through the Turkish Straits, the Bosporus and Dardanelles, are regulated by a 1936 multinational treaty, the Montreux Convention. The convention gives Turkey full control over the straits and guarantees the free passage of civilian vessels in peacetime. The Montreux Convention, which consists of 29 Articles four annexes and one protocol and a principle of freedom of passage and navigation, is stated in Articles 1 and 2. While Article 1 affirms the principle of freedom of passage and navigation by sea in the straits, Article 2 states, "In peace time, merchant vessels shall enjoy complete freedom of passage and navigation in the straits, by day and by night, under any flag with any kind of cargo." However, neither of these articles has a certain definition regarding the transit time of merchant vessels. Therefore, Turkish officials believe that in the case of a slowdown or obstruction of Russian ships, articles of the Montreux Convention will not be violated. In fact the Turkish Straits are one of the most crucial export gateways for Russian exports, and approximately 3 million barrels of crude oil per day flowed through the Bosporus and the Dardanelles last year. Therefore, any slowdown in the export of crude may have a bigger impact on the already shrinking Russian economy.Furthermore, if the Russian side escalates the tension and threatens Turkey with words, Turkey may invoke Articles 20 or 21 of the convention and immediately prevent any Russian military naval vessel from passing through the straits. However, Turkey is not considering playing this valuable trump card, and the passage of the Russian war ship over the weekend is evidence that the country is fully complying with the convention.