Thailand signed an agreement on Friday to import Chinese-made attack submarines.

China Shipbuilding Industry Corp, one of the Chinese Navy's biggest contractors, announced on its website on Monday that the agreement to export the S26T submarine was signed in Beijing by Admiral Luechai Ruddit, chief-of-staff of the Royal Thai Navy, and Xu Ziqiu, chairman of China Shipbuilding and Offshore International Co, the trade arm of CSIC.

The deal marks a new milestone in China's submarine exports, following a deal with Pakistan, CSIC said in a statement, without elaborating. Pakistan has purchased eight attack submarines from the shipbuilder and is awaiting delivery.

Thailand is the third foreign buyer of Chinese submarines in recent years, after Pakistan and Bangladesh.

Bangladesh took delivery in November of two refitted Type 035G-class diesel-electric attack submarines in a $203 million deal.

According to Thai media, the country's navy will spend 36 billion baht ($1.04 billion) to purchase three S26T submarines, an export variant of the Chinese Navy's Type 039A-class diesel-electric attack submarine.

The first payment of 700 million baht might have been paid to the Chinese manufacturer immediately after the signing ceremony on Friday, Thai media reported. The first vessel is expected to be delivered within six years, and the whole order is expected to be fulfilled in 11 years.

The total value of the deal is likely to make it Thailand's most expensive arms acquisition, exceeding its 34-billion-baht procurement of 12 Swedish-made Saab JAS 39 Gripen fighter jets, which were ordered in two batches, in 2008 and 2010.

The last time the Thai Navy had a submarine force was from 1938 to 1951, when it deployed four Japanese Matchanu-class vessels. It has been without submarines since then.

CSIC has yet to disclose the specifications of the S26T, but official information from the Thai Navy, made public at a news conference aboard the HTMS Chakri Naruebet aircraft carrier earlier this month, indicates that the submarine will be equipped with an advanced air-independent propulsion system, which allows a conventionally powered submarine to operate without access to atmospheric oxygen. That means it can stay underwater longer. It will be capable of firing torpedoes, as well as anti-ship and land-attack cruise missiles, the information said.

An industry insider in China's shipbuilding sector who asked not to be named told China Daily on Tuesday that the capabilities of Chinese submarines are good enough to meet the requirements of developing nations, and their prices are competitive. Moreover, China is willing to help buyers develop their own submarine-building industries, which has proved to be a big attraction.

In another development, China North Industries Group Corp, commonly known as Norinco, the country's biggest developer of land armaments, said in late April in a statement on its website that it had signed "an important contract" with the Thai Army. Sources close to Norinco told China Daily that the deal involves the procurement of the Chinese company's VT-4 main battle tanks.

An earlier report by IHS Jane's Defense Weekly said the Thai Army bought 28 VT-4s from Norinco, and that the tanks would be delivered before the end of this year.