Bangladesh took delivery on Monday of its first submarines, bought from China, as it seeks to boost its naval power in the Bay of Bengal.

Bangladesh paid a reported $203 million for the two submarines, a deal that reflects the country’s growing economic and defense ties with Beijing.

Armed forces spokeswoman Taposhi Rabeya said they would become part of the country’s naval fleet at the beginning of next year.

“This is the first ever addition of submarines in Bangladesh defence force,” she told AFP.

Bangladesh has been expanding its defence capabilities in recent years, building a new airbase close to neighboring Myanmar, opening several new military cantonments across the country and adding new frigates to its naval fleet.

In 2013 the government of Prime Minister Sheikh Hasina signed a billion-dollar deal with Russia to buy fighter training jets, helicopters and anti-tank missiles.

Hasina announced the plan to purchase two submarines the same year as part of her government’s move to build a modern navy to defend the resource-rich Bay of Bengal.

A UN tribunal has settled Bangladesh’s long-standing maritime border disputes with neighbors Myanmar and India, paving the way for Dhaka to invite bids from multinational firms to explore for oil in the Bay.

Bangladesh officials say that has ensured the country’s sovereignty over 111,631 square kilometers (43,100 square miles) of sea, an area nearly equal to its landmass.

Xi Jinping last month became the first Chinese president in 30 years to visit Bangladesh, which has historically been more closely allied to rival regional power India.