BEIJING — Some Chinese tour operators have halted travel to North Korea on urging from local authorities and rising safety concerns as Pyongyang whips up war rhetoric following weeks of tension on the Korean peninsula.

Chinese authorities in the northeastern city of Dandong have told tour agencies to halt overland tourism into North Korea, local travel agents said on Wednesday.

"All [tourist] travel to North Korea has been stopped from today, and I've no idea when it will restart," a travel agent in Dandong told Reuters by telephone.

"I think it is because of the situation in North Korea," she said, declining to give her name.

Central government officials said tour groups had stopped travel of their own volition.

"Recently some Chinese travel agents and tourists, on seeing the tense situation on the Korean peninsula, canceled or postponed their travel plans for North Korea," said Hong Lei, a spokesman for China's Ministry of Foreign Affairs. "At present, the China-North Korea border is as normal."

State-controlled CCTV News said the Chinese government had not issued orders to shut down tourism to North Korea.

Four other travel agencies confirmed they had stopped tours that use the land border crossing into North Korea at Dandong. One cited a notice from the government tourism bureau in Dandong.

The border remains open to commercial traffic, the travel agencies said.

However The Pyongyang Project, a Vancouver-based travel and educational exchange group, said via Twitter that a North Korean tourism official in Yanji, another Chinese border city, told them tourism to the North Korean cities of Rason and Chongjin would be unaffected.

Hannah Barraclough, a tour guide with Beijing-based Koryo Tours that organizes visits to North Korea by air, said the company had not received any notice to halt tours.

"It's business as usual for us," she said.

Chinese authorities have temporarily halted travel to North Korea in the past in times of volatility on the Korean peninsula.

North Korean anger over the imposition of U.N. sanctions after its last nuclear arms test in February has created one of the worst periods of tension on the divided peninsula since the end of the Korean War in 1953.

The North ratcheted up threats to attack South Korea and the United States on Tuesday, and warned foreigners in South Korea to evacuate to avoid a "thermonuclear war."

Foreign travel to North Korea is highly restricted, and independent travel without tour agencies is almost impossible.

China, the North's only major diplomatic ally, has repeatedly called for calm and restraint.