This photograph taken on September 28 shows China's Zhang Wenxiu wrapped in her national flag after winning the final of the women's hammer throw athletics event during the 17th Asian Games in Incheon. Asian Games organisers kicked out the gold medal-winning hammer thrower on Friday for failing a dope test.

Reuters/Incheon, South Korea

The Asian Games was hit by yet another doping scandal on Friday when China's Zhang Wenxiu was expelled and stripped of the gold medal she won in the hammer throw.

The Olympic Council of Asia (OCA) announced that Zhang, an Olympic medallist in Beijing in 2008, had tested positive for Zeranol, a banned anabolic agent.

She became the sixth competitor, and the second gold medallist, to fail a drugs test in Incheon, leaving an ugly stain on Asia's biggest multi-sports event, which ends on Saturday.

The announcement came one day after Malaysia's martial arts champion Tai Cheau Xuen lost an appeal to be reinstated after testing positive for a banned stimulant.

Cambodian soft tennis player Yi Sophany, Tajikistan footballer Khurshed Beknazarov, Iraqi weightlifter Mohammed Jasim Abboo Al Aifuri and Syrian karate competitor Nour Aldin Al-Kurdi also tested positive.

News of the latest positive test overshadowed the penultimate day's competition where China won another seven gold medals to take their total to 149, with just seven more to be decided on Saturday before the Closing Ceremony.

Hosts South Korea won another four golds on Friday to lift their total to 77, second overall, while Kazakhstan had an extraordinary day, winning eight golds to remain fourth.

Six of those came in the boxing ring as their amateur pugilists dominated the men's finals.

Middleweight Zhanibek Alimkhanuly and light heavyweight Adilbek Niyazymbetov both scored impressive wins, while flyweight Ilyas Suleimenov took gold in a scrappy split decision win over Uzbekistan's Shakhobidin Zoirov.

"This success comes from the previous generation," said Suleimenov. "Our head coaches are great and the boxing system and facilities in our country are well developed."

Kazakhstan also won gold in the welterweight, heavyweight and super heavyweight divisions, the final bout of the day a clash between Ivan Dychko and Jassem Delavari.

Dychko landed more of the few clean punches that found their mark to earn a unanimous decision.

"I want to celebrate today with my country. We got six golds, one silver and one bronze medal. I'm so happy with this result," he said.

Sri Lanka won their first Asian Games gold medal since 2002 with a crushing 68-run win over Afghanistan in the men's cricket final.

Unlike the previous day, when Sri Lanka won a coin toss to get into the gold medal match after their semi-final with Bangladesh was washed out, luck played no part in the final.

With a strong squad featuring three members of the team that won this year's Twenty20 World Cup, Sri Lanka made 133 then bowled out Afghanistan for just 65.

"This is a great feeling, because this is our first gold medal since 2002," said Sri Lanka captain Lahiru Thirimanne, who top-scored with 57 off just 37 balls.

Afghanistan took the silver medal of the second time a row, a remarkable achievement for a war-torn new to the game.

Most of the country's players learnt to play cricket in refugee camp in neighbouring Pakistan during the occupation by the Soviet Union in the 1980s.

"This is a good sign for us, another silver medal is good," said Afghan captain Mohammad Nabi.

Bahrain won the men's marathon around the streets of Incheon when Kenyan-born Ali Hasan Mahboob crossed the finish line first after seeing off a spirited challenge from Japan's Kohei Matsumara.

Mahboob, who switched nationalities to the gulf country in 2005, is one of a string of African-born runners who have dominated athletics at the Asian Games, provoking strong debate as to whether their success is good for the sport or whether it could lead to a reluctance to invest in home-grown talent.

Another Kenyan-born runner, Eunice Jepkirui Kirwa, also won gold for Bahrain in the women's marathon on Thursday.

Japan won nine medals on Friday but no golds, losing the men's volleyball final to Iran in the last event of the day.

Qiu Bo won the men's 10-metre platform title and He Zi successfully defended her 3-metre springboard as China completed a clean sweep of the 10 gold medals in diving.

Since joining the Asian Games in 1974, China has won every diving event contested, an unbeaten streak stretching 40 years.

Cambodia captured their first ever gold medal at the Asian Games, and their first of any colour since 1970, when teenager Seavmey Sorn women's under 73 kilogram taekwondo event, beating Iran's Fatemeh Rouhani in the final.