BEIJING (AP) — A look at recent developments in the South China Sea, where China is pitted against smaller neighbors in multiple disputes over islands, coral reefs and lagoons in waters crucial for global commerce and rich in fish and potential oil and gas reserves:

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EDITOR'S NOTE: This is a weekly look at the latest developments in the South China Sea, the location of several territorial conflicts that have raised tensions in the region.

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CHINA SHOWS NAVAL AIR EXERCISES ABOVE SEA

China's state broadcaster has shown navy fighter bombers taking part in exercises over the South China Sea, including one involving the detection and expulsion of foreign military surveillance aircraft such as those deployed regularly in the area by the U.S. and others.

The video shown on CCTV's military channel over the weekend shows a squadron of two-seater Xian JH-7 Flying Leopards flying in formation and dropping bombs on targets in the ocean below. Other video showed planes flying just meters (yards) above the ocean surface.

Following that, pilots were "notified that foreign aircraft had entered our airspace to conduct surveillance. One of the planes taking part in the exercise was immediately ordered by the tower to break off and intercept the foreign aircraft," the report said.

That plane increased its elevation and "responded effectively," seizing the commanding position and "successfully expelling" the foreign aircraft, it said.

The report did not say when the exercise took place but said training this year was designed to be more realistic and focused on specific situations, taking the Chinese aircraft to the limits of their range and capability.

"In the process of unceasingly challenging ourselves, the building of our team of talents has entered the fast lane," Tian Junqing, commander of an unidentified South China Sea naval air force regiment, told the station. "The overall combat capability of the force is increasing by stages, forging a formidable force that dares to fight and thunders over the South China Sea."

Missions by U.S. Navy surveillance planes flying in international airspace off the Chinese coast are a particular bone of contention for Beijing.

Twice last year U.S. and Chinese aircraft came close, in one instance to within 15 meters (50 feet) of each other. In August 2014, a Chinese fighter jet came within 9 meters (30 feet) of a Navy P-8 Poseidon reconnaissance plane off Hainan Island — a major military hub — and carried out a series of risky maneuvers, including rolling over it.

In April 2001, a Chinese jet fighter collided with a U.S. surveillance plane over the South China Sea, leading to the death of the Chinese pilot and China's detention of the 24 U.S. crew members for 10 days.

The U.S. and China in 2015 signed rules of behavior to make air-to-air encounters safer, but some analysts say they don't go far enough.

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PHILIPPINE JUDGE LAUNCHES BOOK ON SEA CLAIMS

A Philippine Supreme Court justice has released a book that questions China's historic claims to most of the South China Sea and said he will distribute it online to try to overcome China's censorship and reach its people.

Supreme Court Senior Associate Justice Antonio Carpio said his e-book can be downloaded for free in English now and will be made available later in Mandarin, Vietnamese, Bahasa, Japanese and Spanish to help more people understand the basis of the Philippines' stand against China's territorial claims.

Carpio said public opinion, including in China, can help pressure Beijing to comply with an arbitration ruling last year that invalidated China's historic claims based on a 1982 maritime treaty. Carpio helped prepare the arbitration case, which the Philippines largely won.

China has dismissed the ruling and continued to develop seven artificial islands in the South China Sea's Spratly archipelago. China's construction of the islands on disputed reefs has alarmed rival claimants and the United States.

In the book, titled "The South China Sea Dispute: Philippine Sovereign Rights and Jurisdiction in the West Philippine Sea," Carpio uses old maps, photographs, excerpts from the arbitration ruling, Chinese government statements and documents to question the validity of China's claims.

Carpio warns in the book that China may be planning to build more island outposts at Luconia Shoal off Malaysia and Scarborough Shoal off the northwestern Philippines.

If it constructs an island base at Scarborough, China would have enough radar coverage of the South China Sea to be able to impose an air defense identification zone similar to what it did a few years ago in the East China Sea in a region where it has a territorial dispute with Japan, he said.

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WITH AN EYE ON CHINA, TRUMP MAKES DIPLOMATIC INITATIVE TO SOUTHEAST ASIAN COUNTRIES

U.S. President Donald Trump has made an unexpected diplomatic initiative toward several Southeast Asian counterparts, telephoning Thai Prime Minister Prayuth Chan-ocha and Singapore Prime Minister Lee Hsien Loong to reaffirm traditional close relations and invite them for meetings.

The invitations extended last week followed another one to Philippine President Rodrigo Duterte in a call during which Trump also affirmed America's alliance and friendship with the Philippines and its president, who has maintained an antagonistic stance toward U.S. security policies.

Prayuth's office said he had accepted Trump's invitation, while a Singapore Foreign Ministry statement said the two leaders "looked forward to meeting each other soon." No dates were mentioned for the visits.

Duterte said he has not accepted the invitation because of scheduled trips to Russia, Israel and other countries.

Washington's diplomacy in Asia has focused recently on China and tensions with North Korea, although Vice President Mike Pence included Indonesia on a recent Asia tour.

Washington has strategic concerns in countering Chinese influence in Southeast Asia. Thailand, Singapore and the Philippines are historically the most pro-Western nations in the region, but China's influence has been increasing as it flexes its economic muscle and projects its military power into the South China Sea.

China and the Philippines, along with Brunei, Malaysia, Vietnam and Taiwan have overlapping claims to parts or all of the South China Sea that straddle busy sea lanes and are believed to be atop undersea deposits of oil and gas.

Prayuth's office said he and Trump reaffirmed the importance of their countries' long-standing alliance. It also said Prayuth invited Trump to visit Thailand at a convenient time.

The White House statement about the call to Lee mentioned that "robust security cooperation and close collaboration on regional and global challenges" mark the two countries' partnership.

Chinese President Xi Jinping also spoke by phone last week with Duterte, reflecting radically improved relations between the two governments. China's official Xinhua News Agency quoted Xi as saying the Philippines and China are deepening political mutual trust, carrying out cooperation in various fields, and have set up a channel of dialogue and consultation on the South China Sea.

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Associated Press writers Jim Gomez in Manila, Philippines, and Grant Peck in Bangkok contributed to this report.