The Philippines moved yesterday to contain tensions over a stand-off with China at the disputed Scarborough Reef in the South China Sea, replacing its warship with a civilian coastguard vessel. As diplomacy continued apace, China moved a third civilian ship into the area to join the two marine surveillance vessels guarding the mainland fishermen on eight boats the Philippines wants to arrest after accusing them of illegal fishing last Sunday. Philippines naval officials said they intended to cool tensions at sea as both sides sought a diplomatic solution. 'It is meant to tone down the situation so that the military will not be involved,' said Lieutenant General Anthony Alcantara, head of the Northern Luzon Command that oversees the disputed area. Foreign Ministry spokesman Liu Weimin expressed hopes in Beijing, meanwhile, that the stand-off would not become 'complicated and amplified', and stressed that the Chinese ships involved were not military vessels. Some mainland internet users, however, called on Beijing to take tougher action against the Philippines. 'The Philippines sent a military ship, but we only sent patrol ships. It is shameful,' said one internet user on Sina Weibo. State media said China had exercised restraint by sending only patrol ships to the disputed waters, but added that Beijing would take further action if tensions escalated. 'Peace and stability in the area are still what China strives for but it will not make unprincipled concessions to the recklessness of neighbouring countries,' said an editorial by the Global Times newspaper, published under the People's Daily. Philippines presidential spokesman Edwin Lacierda said he could not say whether his side was prepared to open fire but said that if the Chinese side attacked, 'certainly the president has informed the navy to observe the rules of engagement.' He said Foreign Secretary Albert Del Rosario was 'hopeful for a resolution'. Zhuang Guotu, director of the Centre for Southeast Asian Studies at Xiamen University, expected the stand-off to be resolved. 'Both sides do not want a war. The Philippines is well aware that the military strength of itself and other South China Sea claimants are not comparable to that of China,' he said, adding that Chinese patrol ships are sophisticated enough to handle military threat by the Philippines. Scarborough Reef is 124 nautical miles from the main Philippine island of Luzon - Manila claims that puts it within its 200-nautical mile exclusive economic zone under the UN's international sea law. It sits within China's so-called nine-dotted line that encompasses much of the South China Sea. Tensions rose last year as Manila accused Chinese ships of harassing Philippine fishing and oil exploration vessels. The latest stand-off is being closely watched around the region, coming just ahead of annual military drills between the Philippines and the US on the island of Palawan, close to the disputed Spratly islands. While the Scarborough Reef is claimed by the Philippines and China, the highly strategic Spratlys are claimed in part by the Philippines, Malaysia and Brunei and in whole by China and Vietnam. Taiwan's claim mirrors that of Beijing.