Chinese media reported Thursday that most of the country's travel agencies have suspended trips to the Philippines amid an escalating war of words over a disputed island chain in the South China Sea.

Chinese authorities also issued a safety warning to its citizens in the Philippines due to planned anti-China protests later this week, and demanded that Manila ensure the safety of Chinese nationals.

The standoff began April 10 when Chinese surveillance ships prevented authorities on a Philippine warship from arresting Chinese fishermen in the contested water near the Scarborough Shoal, which is known as Huangyan in China. It is part of a wider territorial dispute in the South China Sea, parts of which are also claimed by Vietnam, Taiwan, Malaysia, and Brunei. China claims nearly the entire region, which is thought to contain large amounts of oil and natural gas.

Conflicts among claimants are nothing new. In the 1970s, they have led to arrests of Chinese and Vietnamese fishermen and even brief naval battles between China and Vietnam. However, worries are growing about the possibility of greater conflicts as China asserts its power and influence to claim resources and Washington backs up the Philippines with increased arms sales.

To ease tensions, the Association of Southeast Asian Nations has been negotiating details on a code of conduct in the South China Sea. The deadline for reaching an agreement is July 2012.

Earlier this week, China's Foreign Ministry said it was not optimistic about resolving the dispute with the Philippines and warned it was ready to respond to “any escalation” by Manila.

Chinese state media on Thursday hinted at the possibility of war if the dispute is not resolved soon. An editorial in the official China Daily said Beijing prefers a peaceful solution, but insisted that Manila is “pressing us into a corner where there is no other option left but the use of arms.”