As the Philippines seeks to buy weapons abroad amid a diplomatic crisis with China over the two countries' territorial dispute in the South China Sea, Beijing warned on Tuesday that any attempt by a third country to get involved in the territorial dispute over Huangyan Island between Beijing and Manila will only make the situation worse.

On April 10, a Philippine warship harassed 12 Chinese fishing vessels that had sailed near Huangyan Island, which is part of China's territorial waters in the South China Sea, to seek shelter from a storm. The incident later escalated into a month-long dispute between the two countries.

"The Philippine decision to draw a third party into the incident in any way will further escalate the situation and even change the nature of the issue," Hong Lei, foreign ministry spokesman, said at a regular media briefing.

The comments came as the United States is scheduled to deliver a retired Hamilton class cutter to Manila on Tuesday. This will be the second Hamilton class cutter Manila has obtained from the US.

The first one, also retired from the US, arrived in the Philippines last year, giving the Philippine navy its largest and most advanced warship.

Moreover, Philippine President Benigno Aquino told media outlets that Manila intends to buy a batch of jets ranging in price from $4 million to $8 million.

Albert del Rosario, Philippine foreign affairs secretary, said some other countries are helping Manila establish a "minimum credible defense posture" to complement its diplomatic capacity to deal with territorial disputes with China.

Rosario told media on Sunday that at least three nations besides the United States are on the list - Japan, South Korea and Australia.

He said Japan is likely to provide 12 patrol ships, while the Philippines is considering entering into plane deals with South Korea. The Philippines are also likely to obtain some search and rescue ships from Australia and have a large number of military personnel trained there.

A 47-year-old Hamilton class cutter that was purchased last year from the US was sent to arrest the Chinese fishermen involved in the April 10 incident and was confronted by two Chinese maritime patrol ships. It retreated soon and was replaced by patrol boats.

Qu Xing, director of the China Institute of International Studies, said Manila can improve its military by purchasing arms. But its military can by no means be compared with China's, which is also developing.

And with the Philippine economy performing worse since Aquino became president, the country will face rising financial dangers if it spends too much on its military, Qu said.

Song Xiaojun, a Beijing-based commentator, said the plan to buy arms shows that the government has more or less been "kidnapped" by the military, which Manila depends on in its fights against anti-government forces.

The Aquino administration has spent $395 million on the country's military since it took office in 2010. In the 15 years up to that, Manila spent $51 million on average, Song said.

"And even the Philippines itself knows there is something wrong in their logic of one hand taking massive preferential loans from China and one hand using that money to buy weapons."

Major General Xu Yan from the National Defense University of the People's Liberation Army said in an article published on Monday that China has absolute advantage in air and naval forces over the Philippines.

"Once (the Philippines) dares escalate the movements of maritime police into military operations, it will suffer a great calamity from China's strike in response to their attack."

In the past, it usually took two days for Chinese ships to arrive in the waters around Huangyan Island, but China now has "a large batch" of large and advanced ships that it can use in maritime patrols, Xu wrote.

Xu said the Philippines used to arrest and even shoot at Chinese fishermen who were near the island in the 1990s.

"But those days are gone."