Five lawmakers of the main opposition Democratic Party are on a visit to China, sources said Wednesday, amid heightened tensions between the two countries over Chinese Ambassador Xing Haiming's remarks, which were strongly denounced as disrespectful to South Korea.

The lawmakers -- Reps. Kim Tae-nyeon, Hong Ihk-pyo, Koh Yong-jin, Hong Kee-won and Hong Sung-kook -- arrived in Beijing on Monday for a five-day visit for meetings with people from Chinese political and business circles, the sources said.

Sources said the trip was arranged at China's invitation.

The trip came days after the Chinese ambassador sparked a furor by saying "those who bet" on China's defeat in its rivalry with the United States "will definitely regret it," during a meeting with Democratic Party leader Lee Jae-myung on Thursday.

The remarks were interpreted as a warning to Seoul against aligning itself with Washington.

South Korea's foreign ministry summoned the envoy and issued a strong warning. The presidential office also said it is waiting for Beijing to take an "appropriate measure," apparently pressuring China to take measures to recall its envoy.

The ruling People Power Party lashed out at not only Xing, but also Democratic Party leader Lee, accusing him of providing the envoy with a chance to make such remarks. The five Democratic Party lawmakers could come under fire for making the trip at the wrong time.

"Though Korea-China relations are not at ease, this visit is aimed at seeking improvement in relations as China is important for our businesses and the economy," a Democratic Party official said. "This has been scheduled for several months." (Yonhap)