Two missile frigates that have protected civilian ships against Somali pirate attacks arrived in Hong Kong for a four-day call yesterday. The ships, Zhoushan and Xuzhou, from the PLA Navy escort task force 529, will be berthed at Stonecutters Island barracks before returning to their base in Zhejiang province on Thursday. A total of 4,800 tickets were distributed on Sunday for members of the public to visit the ships between yesterday and tomorrow. Armed with artillery, ship-to-ship and anti-aircraft missiles, the frigates are among the PLA Navy's most advanced. They also boast a helicopter, which can be used to deploy elite soldiers of a special operations unit. The task force was the third sent to fend off pirates in the Gulf of Aden. During its four-month mission it escorted 582 ships, including those registered on the mainland, in Taiwan, Hong Kong and 29 foreign countries and territories, breaking a monthly record for the navy. Rear Admiral Wang Zhiguo, commander of the task force, said it had faced harsh conditions. Some officers had suffered from insomnia, eating difficulties and other sicknesses as a result. The crew was greeted by Chief Executive Donald Tsang Yam-kuen. A group of primary school pupils waved flags to welcome the officers. Ma Ding-shing, a Hong Kong-based military commentator, said the two frigates were an example of China's advanced weapons, but they might not be the most effective tool for the task. 'It is showing off China's military power ... these ships are designed for real wars. To fight Somali pirates it would be enough to send patrol vessels.' Ma estimated that each of the frigates cost at least US$300 million, adding that it would be at least one-fifth cheaper to send semi-military ships.