The two new warships that China has sent to the Gulf of Aden and Somali waters are a destroyer often used in diplomatic missions and the latest frigate with radar-hiding functions.

The new ships, destroyer Shenzhen and frigate Huangshan, will relieve two destroyers in the piracy region, Wuhan and Haikou, for another tour of duty that is likely to last at least three months.

The warship DDG-167 Shenzhen is the sole missile Type 051B destroyer of the People's Liberation Army Navy. It entered naval service in 1999 with a displacement of 6,000 tonnes and carrying anti-ship missiles, surface-to-air missiles, close-in weapons systems and an anti-sub helicopter.

The Shenzhen destroyer has been the naval name card of China as it has carried out most of the Navy's diplomatic visits to overseas ports.

The warship has traveled to more than 10 countries and regions in Europe, Asia, Africa and Oceania with a total voyage that exceeds 100,000 nautical miles.

FFG-570 Huangshan, the Navy's latest frigate model, is one of the Type 054 series. The expedition to the Gulf of Aden and Somali waters is the frigate's public debut although it has taken part in several naval drills.

Designed and manufactured by a Chinese shipbuilder, the frigate has been given several radar-hiding features such as a sloped superstructure which blends into the ship's hull, reduced surface equipment and radar absorbent materials.

Similar to destroyer Haikou in the Gulf, the frigate Huangshan could also provide the flotilla with a mid-range aerial defense capability. The ship-borne vertical-launched missile system could handle threats from all engagement angles.

The supply ship, Weishanhu (pennant number 887) of the Navy's Qiandaohu class, which stays on station awaiting the new ships, has provided a three-month long support to the warships with only one port call in Yemen.

Having a displacement of 23,000 tonnes and maximum speed of 19 knots, Weishanhu is the biggest homemade multi-product replenishment ship. Although its primary role is supply, it can also defend itself and take part in offensive operations using its eight 37mm guns.

All the warships sent to the region belong to the South China Sea Fleet, headquartered in Zhanjiang in Guangdong Province.

The commander of the task force which set sail on Thursday is Real-Admiral Yao Zhilou, who serves as deputy commander of the South China Sea Fleet.

En route to the Gulf of Aden and waters off the coast of Somalia, the commander told the Xinhua reporter onboard that he and his crews were fully confident of fulfilling the mission and willing to share information with other navies to protect the merchant vessels.