The nation's top tourism industry authority called on Thursday for measures to cap visitor numbers amid chaotic scenes at some of China's top attractions.

The National Tourism Administration urged tourism authorities to take the measures as the nation witnessed a travel peak due to the seven-day National Day holiday, which started on Tuesday.

The statement was released after tens of thousands of tourists were stranded for hours on Wednesday at Sichuan province's world-famous Jiuzhaigou Valley.

Police were sent to the park to calm the situation as some angry tourists even forced shuttle buses to stop after they failed to get on, causing hours of delays.

The administration's statement said most major attractions are seeing surging numbers of visitors, which requires better service and management by local governments.

According to the Tourism Law, which came into effect on Tuesday, authorities should have emergency plans such as visitor flow control to deal with excessive numbers of visitors to tourist destinations.

Jiuzhaigou, which is famous for its multi-level waterfalls, lakes and snow-capped peaks, stretches over almost 73,000 hectares and can accommodate about 41,000 visitors per day. Tourists rely on electric shuttle buses — the only transportation allowed on the site — to get around. It takes hours to walk from one bus stop to another inside the park.

As visitors are not allowed to stay overnight in the park, many say they were forced to walk for about 5 kilometers before they could catch a bus to leave the valley.

The local tourism bureau apologized in a statement on Thursday, saying that all stranded visitors had been able to leave the park by 10 pm.

As of 7 pm on Wednesday, more than 4,000 tourists had been stranded in the valley, according to the bureau.

The bureau pointed out that some visitors had trespassed onto the main road used by buses, which had worsened these delays.

Jiuzhaigou authorities said all 400 buses were running and tourists had blocked the roads and caused massive congestion.

The bureau promised to refund tickets sold on Wednesday, worth 300 yuan ($48) each, and more than 11,000 tickets had been refunded as of 11 am on Thursday.

Large crowds were observed in tourist spots across China this week as millions of people traveled for their seven-day holiday. According to the China National Tourism Administration, more than 10 million people took the train on Tuesday, up around 13 percent.

On Tuesday, around 110,000 people watched the flag-raising ceremony at Beijing's Tian'anmen Square, leaving around 5 metric tons of trash behind them.

On the same day, the Palace Museum in Beijing received 175,000 visitors, about 7,000 fewer than the record last year.

The scenic West Lake in Hangzhou, Zhejiang province, received millions of visitors, who left behind more than 7,000 cigarette butts for sanitation workers to clean up on Wednesday.