A German badminton coach and a team entourage member from France have tested positive to coronavirus within the so-called tournament bubble of the Thailand Open, a day after tests showed an Egyptian player was infected.
The Thailand Open is the first of three consecutive restart tournaments in Bangkok as badminton resumes after a coronavirus-ravaged 2020.
The pair are under observation in a Bangkok hospital where they must stay for a minimum of ten days, the Badminton World Federation said late on Wednesday.
The federation said all players who underwent a test on Tuesday had returned negative results and strict contact tracing protocols had been activated.
On day one of the tournament, there was a kerfuffle over four players' test results and two Indian shuttlers were sent to hospital but later released.
The federation later confirmed out of the four, subsequent tests showed only Egyptian mixed doubles player Adham Hatem Elgamal had the virus and withdrew from the tournament.
Indian star Saina Nehwal was among three other players who initially tested positive but were allowed to play because their infections were historic.
Thailand's badminton chief last month told AFP the tournaments would be the "safest in the world".
On court Spain's Carolina Marin sailed through the first round on Wednesday as she made a fast start to her season, six months before her Olympic title defence.
The former world number one made short work of France's 37th ranked Qi Xuefei, winning the first game in just 15 minutes before sealing it 21-10, 21-12.
"I feel really happy to be back on court after some months without tournaments. I have really missed it a lot," said Marin.
"I wanted to get back this competition feeling, that adrenaline. I came with determination to win but also to keep my focus on my game plan.
"Winning here is what I want. I would like to win a title here."
It was the 27-year-old's first international outing since losing the Danish Open final in October.
Thailand's best hope, former world number one, Ratchanok Intanon is through to round two after polishing off Singapore's Yeo Jia Min, ranked 26 in straight sets; 21-15, 21-15.
In the men's singles, third seed Anders Antonsen made a surprise early exit in the first round going down to Malaysia's Liew Daren ranked 41st: 21-12, 21-18.
"Before this tournament I didn't know I would even play because I was on the reserves list, so to make it at the last minute and also win my first round against the third seed, it has really surprised me," Liew said, adding in the lead up his training had been disrupted by a coronavirus lockdown.
Meanwhile, Thailand's Tanongsak Saensomboonsuk ranked 39th forced world number two Taiwan shuttler Chou Tien-chen into a three set decider.
The local came out firing in the first game 16-21 but quickly lost momentum going down 21-10, 21-14.