LONDON — Chinese stocks led global markets lower Friday after plans were announced to sharply limit new vehicle registrations in traffic-congested Beijing, while the latest downgrade of Portugal's credit rating kept sentiment in check in European markets.

Trading generally was light with many markets, including Wall Street, closed for Christmas.

In Europe, France's CAC-40 closed down 0.3 percent to 3,900.39, while Britain's FTSE 100 ended up 0.2 percent at 6,008.92, its first close above the 6,000 mark since the summer of 2008.

Both markets were only open for half the day while those in Germany and many other places in Europe were closed.

A downgrade late Thursday of Portugal's credit rating from Fitch Ratings weighed on the markets. Fitch reduced its rating on the country's debt by one notch to A+ from AA- and warned that further downgrades may be in the offing. The agency said it was getting increasingly worried over Portugal's ability to raise money in the markets to finance its hefty borrowings.

Portugal is widely considered to be the country most at risk in the 16-nation eurozone of needing financial help from the European Union and the International Monetary Fund — Greece and Ireland have already suffered the ignominy of being bailed out.

Concerns over Europe's debt crisis have not stopped Europe's stocks rising strongly this year and enjoying their best December for ten years.

"The prolonged Santa rally has left the market looking strong ahead of the holidays and there is still the potential for further gains before the end of the year, with post-Christmas trading sometimes producing exaggerated moves due to thin volumes," said David Jones, chief market strategist at IG Index.

The euro has not enjoyed the same sort of rally, as worries that the debt crisis will spread continue to undermine confidence.

The impact of the Portuguese downgrade was muted however, given lackluster trading conditions, though the debt crisis will likely be a major influence once traders in Europe return in the new year.

"Growth prospects for the eurozone are mediocre, and the attention will remain on any new developments in the sovereign crisis," said Herve Goulletquer, an analyst at Credit Agricole.

By early afternoon London time, the euro was flat at $1.3120, while the dollar was unchanged at 83 yen.

Earlier in Asia, the Shanghai Composite index declined 0.7 percent to 2,835.16 and the Shenzhen Composite Index for China's smaller, second market fell 1.8 percent to 1,292.02. Hong Kong's Hang Seng Index closed 0.3 percent lower at 22,833.90

Carmakers led the retreat, with Dongfeng Motor Group., which operates a joint venture with Nissan Motor Co., tumbling 7.9 percent on the Hong Kong exchange. Geely Automobile Holdings, which bought Sweden's Volvo Cars from Ford Motor Co. earlier this year and is also listed in Hong Kong, dropped 6 percent. Shanghai Automotive Industry Corp., which has joint ventures with General Motors and Volkswagen, fell 2.3 percent in Shanghai.

Analysts said automakers were hit by news that Beijing is planning to sharply limit new vehicle registrations to try to ease the city's massive traffic jams.

The city will only let 240,000 vehicles to be registered next year, said Zhou Zhengyu, vice secretary general of the Beijing city government. The figure is a little more than one-third of the total number of new cars on the capital's streets this year.

The auto industry has been a key motor of China's economic boom and any attempts to contain it will hurt the country's economic growth.

Elsewhere in Asia, the Nikkei 225 stock average lost 0.6 percent to 10,279.19, reopening after a national holiday Thursday.

Benchmark oil for February delivery rose 93 cents to $91.41 in electronic trading on the New York Mercantile Exchange.

AP Business Writer Kelvin Chan in Hong Kong and researcher Ji Chen in Shanghai contributed to this report.