TOKYO (AP) — China's stock market fell sharply Friday as investigations into the securities industry widened to include two top brokerages.

Most other Asian markets were lower in muted trading after Wall Street was closed for the Thanksgiving holiday, and investors continued to watch for developments in tense relations between Russia and Turkey.

KEEPING SCORE: China's Shanghai Composite was down 5.5 percent at 3,436.30 after earlier falling more than 6 percent. Japan's benchmark Nikkei 225 retreated 0.3 percent to 19,883.94 and South Korea's Kospi fell 0.1 percent at 2,028.99. Hong Kong's Hang Seng dropped 1.9 percent to 22,062.68. Other regional markets were also lower, falling in Taiwan, Australia, the Philippines, Indonesia and Singapore. Thailand's benchmark rose.

CHINA PROBE: Two major Chinese brokerages announced they are under investigation for possible violation of securities market rules in the latest aftershock of this summer's market plunge. A string of Chinese securities executives have been detained or questioned following a plunge in share prices that began in early June. The investigations were seen by many as an attempt by the ruling Communist Party to deflect blame for a market bubble that it engineered.

RUSSIA AND TURKEY: Markets have been wary about geopolitical tensions after Turkey downed a Russian plane that entered its territory from war torn Syria. Russian President Vladimir Putin has said his nation is ready to cooperate with the U.S.-led coalition fighting the Islamic State group, while criticizing the U.S., saying it should have prevented its coalition ally Turkey from making such a move.

THE QUOTE: "Russia has threatened to retaliate economically against Turkey in response to the shooting down of its warplane, but both sides appear keen not to escalate any military tensions despite a war of words," said Chang Wei Liang of the Singapore Treasury Division of Mizuho Bank. "With Russia-Turkey economic ties being rather small in the context of the global economy, we think that risks of spillovers to the global recovery are rather small."

WALL STREET: New York trading was closed for the Thanksgiving holiday, but it's set to reopen Friday for an abbreviated session. Much of the interest will likely center on retail stocks because of Black Friday, when millions of Americans venture to shops the day after Thanksgiving in search of bargains.

ENERGY: Benchmark U.S. crude was down 65 cents to $42.39 a barrel in electronic trading on the New York Mercantile Exchange. Brent crude, a benchmark for international oils, lost 27 cents to $45.19 a barrel in London.

CURRENCIES: The dollar was little changed at 122.41 yen from 122.62 yen on Thursday. The euro rose to $1.0626 from $1.0607.

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