LONDON, England (AFP) — American world champion Carmelita Jeter fired a warning to Jamaica's sprint queens yesterday, qualifying quickest for the semi-finals of the Olympic women's 100m in a blistering time of 10.83sec.

Jeter's run, which would have been enough to win a silver medal at the 2008 Beijing Olympics, put her 0.10sec ahead of Nigeria's Blessing Okagbare, who set a personal best of 10.93sec to win her heat.

Jamaica's Veronica Campbell Brown, a two-time Olympic 200m champion and 100m world champion in 2007, was third quickest in 10.94sec with her Jamaican teammate and defending Olympic champion Shelly-Ann Fraser-Pryce, seventh fastest with 11.00sec.

The semi-finals and final take place today.

"I just had to come out and execute like my coach wanted me to do. I still have two more rounds to go. Everybody's going to definitely be running their hearts out tomorrow," said 32-year-old Jeter.

"The track felt good and I'm excited to be here. I feel so blessed to be here, so happy. This is what I've worked so hard for and it's an experience like never before," added Jeter.

Okagbare said she felt confident for the rest of the competition after her first outing, adding: "I'm really excited about this, with the way I ran and a personal best already."

Campbell Brown, who won 100m bronze in Athens in 2004, said: "I believe a true champion needs to be able to deal with fear. I'm hoping we can get two Jamaicans in the final."

Fraser-Pryce said she was not pleased with her start but was relieved to qualify.

"I have come a long way in the past four years. There is a lot of hard work, but I don't know if I can make the grade until tomorrow night," she said.

"I have no fear. God has brought me here. It all comes down to who wants it the most."

World 200m champion Allyson Felix, who is yet to win a medal in the 100m at the global level, qualified controversially for the event when Jeneba Tarmoh withdrew from a scheduled run-off after the two finished in a dead heat for third place at the US trials.

"I missed the start but other than that I was happy with my acceleration and all that, so I'm definitely going to put it together for the next round," Felix said.

"It's just amazing to be here," she added. "I'm focusing on the 200, but I also like the one (100 metres). I think the speed and the rhythm of both benefit me and I'm excited to step it up tomorrow."