Rio 2016 spokesman Mario Andrada Tuesday downplayed concerns over slow ticket sales, saying he expected a late surge would see Summer Olympic venues filled come August.

"Brazilians are late buyers," Andrada told reporters at the US Olympic Committee's pre-games media summit in Beverly Hills. "Sometimes people get nervous. There is no problem, we are going to sell all the tickets."

Games organizers in Brazil revealed last week that fewer than half of all tickets had been sold with just over five months to go before the opening ceremony on August 5.

It was just one more worry for Games organizers already coping with the outbreak of mosquito-transmitted Zika virus and concern over polluted water at the sailing venue at Guanabara Bay.

Andrada, communications director for the Rio organizing committee, faced a barrage of questions on those topics, as well as on the race to complete venues and a new metro line bypassing congested highways between the center and west of the city.

"As a matter of fact, from 44 test events, only one will be delayed, which was track cycling," he said.

"We are almost there. The velodrome is going to be ready for the test event, the subway will be ready for the Games very close to the Games," he said.

Andrada reiterated the steps being taken in Brazil to eradicate mosquitoes in a bid to lower the danger of Zika -- which causes only mildly flu-like symptoms in most people but has been linked to a rise in the birth defect microcephaly.

And despite criticism by sailors around the world, including former windsurfing gold medallist Lee Lai-shan of Hong Kong, he said he was "totally confident 100 percent" that the venue could host a "fair competition with no risk to the health of the athletes."

Amid the scrutiny of those issues, other projects are moving forward, Andrada said.

He said the Rio Olympic slogan will be unveiled within the next three weeks.

He said the medal design has been approved by the International Olympic Committee, and the ticket design has been confirmed -- although partly in a bid to prevent counterfeiting it won't be unveiled until closer to the Games.

Andrada also said that while the Games will not have multiple cauldrons for the Olympic Flame, the lone cauldron could be moved after it is lit at Maracana Stadium during the opening ceremony -- from the fabled football stadium to the athletics stadium.

"That's a possibility," Andrada said.

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