Russia and Syria have signed an agreement on expanding and modernizing Russia’s Tartus naval base in Syria, a Russian government document showed.

The agreement envisages that 11 Russian warships can be located in the Tartus base at one time, the document added.

According to the document posted on the Russian government’s legal information portal Friday, the agreement on Russia’s naval maintenance facility in Tartus is defensive in nature and is not directed against other countries.

“The presence of the Russian naval maintenance facility on the territory of the Syrian Arab Republic meets the objectives of maintaining peace and stability in the region, is defensive in nature and is not directed against other states,” the document stressed.

It said Russia will ensure the defense of the naval maintenance facility in Tartus from air and sea, while Syria will defend it from land.

Furthermore, Russia and Syria have signed a protocol to the agreement on the Russian Aerospace Forces’ airbase in Syria, which envisions deployment of Russian aircraft free of charge at a section of the Hmeymim airfield, according to the same document.

The protocol was signed by both parties January 18, 2017 in two originals, each in the Russian and Arabic languages, with both texts having equal legal effect.

In October 2016, Russia’s Defense Ministry said Tuesday that it had sent an S-300 missile system to its naval facility in Tartus, a measure it said is meant to bolster its security.

“The S-300 anti-aircraft missile system has indeed been sent to the Syrian Arab Republic,” Defense Ministry spokesman Igor Konashenkov said in a statement.

The officials said the new weapon system could potentially counter any US cruise missile attack in Syria.

This makes it the first time Russia has deployed the S-300 system outside its borders.