Portugal Colonial - Russia's Valieva aims for second Olympic title under doping cloud

The 15-year-old is in pole position after finishing top in Tuesday's first half of the women's singles competition, before the all-important free skate that starts at 1000 GMT.

In early action, Eileen Gu put herself on track for a third freestyle ski medal for China while Mikaela Shiffrin was in the driving seat for the alpine combined event as the American skier sought to salvage her disastrous Olympics.

But all eyes will once more be on Valieva. If she finishes in the top three, medals will not be presented, in an unprecedented move for the Olympics.

Valieva's doping case has dominated the second week of the Games in the Chinese capital after the Court of Arbitration for Sport (CAS) ruled that she could continue to skate in the Olympics despite failing a drugs test in December.

Before her positive test was announced, she played a central role in helping the Russians to skating team gold last week, becoming the first woman to perform a quadruple jump in Olympic competition.

No medal ceremony took place for that event either because of Valieva's involvement.

IOC president Thomas Bach met the second-placed US team from the team event on Wednesday, but the IOC refused to comment on reports that Bach offered the skaters Olympic torches in lieu of their silver medals.

When CAS cleared Valieva to stay at the Games, it cited her young age as one of the "exceptional circumstances", but she has not been absolved of doping and the investigation looks set to rumble on well after the action ends in Beijing.

The teenager tested positive for trimetazidine, a drug used to treat angina but which is banned for athletes by the World Anti-Doping Agency (WADA) because it can boost endurance.

US media have reported that her sample also contained the substances Hypoxen and L-Carnitine, which are also used to treat heart conditions. They are not on WADA's prohibited list.

The affair puts the spotlight once more on the participation of Russian athletes at Olympic Games.

They are taking part in Beijing under the banner of the Russian Olympic Committee because Russia as a country is serving a two-year ban as punishment for a state-sponsored doping programme.

In another doping case, Games' testers said Ukrainian cross-country skier Valentyna Kaminska had tested positive for an anabolic steroid and two banned stimulants.

Her highest placing in two individual events was 70th.

- Gu and Shiffrin poised -

Californian-born freestyle skier Gu, competing for China, has become one of the faces of the Beijing Games and the 18-year-old put herself firmly in contention to win a third medal, and second gold, by finishing easily top of qualifying in the halfpipe.

Double Olympic champion Shiffrin made a good start in the alpine combined as she attempted to win a first medal at this Games.

The American failed to finish her first two events, before finishing way out of the medals in the next two.

But she was perfectly poised to win a medal in the combined after posting the fifth-fastest downhill time ahead of the slalom -- a discipline in which she is a four-time word champion and Olympic gold medallist in 2014.

In a sign of the support she is receiving from her competitors, Shiffrin revealed she had used skis for the downhill belonging to Italian Sofia Goggia, who won a silver medal in the downhill proper.

"She actually wrote a small message on them... I saw it and I almost started crying," Shiffrin said.

Canada and the United States face off for the gold medal in the women's ice hockey, but North America's involvement in the men's competition was ended when Sweden beat Canada in the quarter-finals on Wednesday.

After Thursday's early action, Norway top the medals table with 13 golds, Germany have 10 and the United States have eight.

A.Santos--PC