Russia plans to invest $500 million in the Syrian port of Tartus and build a grain hub, Deputy Prime Minister Yuri Borisov said on Tuesday. Mr Borisov made the announcement on a two-day visit to Syria, during which he met with Syrian President Bashar Al Assad. Mr Borisov’s office said the trip would focus on “the operation of the port of Tartus, which was leased by Russia, and options for customs preferences to supply Syrian agricultural products to Russia from citrus, olive and olive oil.” Russia, the world's largest wheat exporter, has stepped up grain supplies to support Syrian President Bashar Al Assad in recent years since Moscow's 2015 military intervention on his behalf in Syria's civil war. Construction of the necessary infrastructure at the port, which Russia rented out for 49 years from Syrian authorities in 2017, could begin next year, Mr Borisov said. Syria's Mediterranean coastal region has remained under firm government control throughout the war. "Russia intends to organise the work of the old port and to build a new commercial port,” Mr Borisov said. “The sum of investment for the next four years is valued at $500 million.” Moscow will also begin delivering 100,000 tonnes of grain in humanitarian aid to Syria by the end of December - supplies that will continue until mid 2020. Ports in Crimea, which Russia annexed from Ukraine in 2014, have exported the Black Sea peninsula's surplus of grain to the port of Tartus in recent years to ensure Assad's Syria has a reliable source of food. The Russian Navy also operates a military facility at Tartus, Russia's only naval foothold in the Mediterranean, and Moscow has previously said it plans to expand and modernise the port's facilities for its fleet. The port can currently hold 11 warships, making it a crucial part of the country’s military presence in the Middle East. Earlier on Tuesday, the Russian Defence Ministry's Zvezda TV channel said Russia and Syria had carried out their first joint military drills near Tartus. The drill involved more than 2,000 Russian and Syrian troops, 10 naval vessels as well as Russian aviation, the Zvezda report said. Russia also has an air base in Syria's coastal Latakia province which it has used for air strikes against forces opposed to Assad. Last month, Moscow said it had set up a helicopter base at an airport in northeastern Syria.