Beijing (CNN) While the world celebrated the rescue of 12 boys and their soccer coach from a flooded cave in northern Thailand, in China frustration and anger have grown over Thai authorities' handling of the sinking of two tourist boats which left more than 40 people dead.

The two boats carrying more than 120 Chinese tourists capsized and sank in a huge storm last Thursday off the resort island of Phuket. Several passengers were still missing almost a week later.

A huge backlash against Thailand ensued after the country's deputy prime minister, Gen. Prawit Wongsuwan, blamed Chinese tour operators in Phuket for the deadly accident.

"This accident was entirely Chinese harming Chinese," Prawit was seen telling local reporters Monday in a widely circulated video . "The boats were theirs, and they ignored warnings and insisted on sailing out to sea. We weren't responsible for that -- they were. They have to resolve this themselves."

Chinese social media and official newspapers responded harshly to Prawit's comments, forcing a hasty apology.

The state-run China Daily called his comments "provocative and irresponsible."

"Even if what he said is true, the Thai government cannot shirk its responsibility for guaranteeing the safety and security of tourists," it said.

Users on the Twitter-like service Weibo, citing witnesses who were at the scene, said there was no official warning in Phuket against sailing when the ship left port, before it encountered inclement weather at sea.

They also questioned the actions of the boats' Thai crews, who reportedly abandoned passengers when water rushed in.

Some claimed survivors and grieving families arriving from China faced red tape and bureaucratic delays when trying to see and identify the bodies of their loved ones.

"Can China be so easily bullied now -- and Chinese lives be so carelessly trampled on?" one popular Weibo post read Wednesday. "I'm happy for the Thai soccer boys who were rescued, but I will never go visit that country again!"

A Chinese relative cries at the Vachira Phuket Hospital in Phuket on Sunday.

Calls for a boycott

China is the biggest source of foreign visitors to Thailand, where tourism is a major industry. Almost 10 million Chinese nationals visited Thailand last year, according to official statistics.

Amid rising calls in China to boycott Thailand, the military government in Bangkok seems to have switched to damage-control. On Tuesday Thailand's embassy in Beijing issued a statement saying Prawit's remarks "may have traumatized families of the victims," and that the general expressed his "regret and apology" to the Chinese tourists in the accident.

"Thailand will provide the best and fairest treatment to all tourists affected by this accident," it added. "We will work closely with China to formulate preventative measures to avoid similar accidents from happening again."

Thai rescue and paramedic personnel attend to rescued passengers of capsized tourist boat in rough seas at a port in Phuket on Thursday.

Following the Thai embassy statement Tuesday, the Chinese government appeared to move to dampen public criticism, reiterating that the ongoing search and rescue missions conducted by the Thai authorities and highlighting Thai Prime Minister Prayut Chan-ocha's visit to hospitals where injured Chinese tourists were being treated.

"The search area has been expanded," said Hua Chunying, a Chinese foreign ministry spokeswoman. "The Thai side promised that their search efforts will not cease until every missing Chinese tourist is found."

She added that the "Thai police will find out the cause of the accident as soon as possible and figure out the parties who are to blame for the accident and hold them accountable with no tolerance."

Phuket Governor Norraphat Plodthong told CNN that a Chinese team has been working with Thai authorities in the rescue effort. He declined to comment when asked about Prawit's comments.

But for some Chinese, though, the Phuket accident seems to have become a turning point in their perception about Thailand.

"(We) were sending well wishes and prayers to the Thai soccer team boys trapped in the cave and China even participated in the rescue," a Weibo user wrote Wednesday.

"It was disgusting and chilling to see that Thai deputy prime minister to wave off their responsibility in the Phuket boat accident after so many Chinese tourists perished."