BEIJING (REUTERS) - China's Foreign Ministry declined to say on Monday whether President Xi Jinping had held talks with a senior North Korean official visiting for a military parade last week, underscoring the parlous relations between the two supposed friends.

Choe Ryong Hae, secretary of the Central Committee of North Korea's Workers' Party, was in Beijing to attend the parade marking 70 years since the end of World War Two in Asia. Choe is close to North Korean leader Kim Jong Un.

Xi did, however, hold a high profile meeting with South Korean President Park Geun Hye, in Beijing for the same event.

"President Park Geun Hye and Secretary Choe Ryong Hae were both guests invited by China, and both received warm and friendly treatment from China," ministry spokesman Hong Lei said, when asked if Xi and Choe met aside from when Xi greeted foreign guests at the beginning of the parade. "China is dedicated to developing a friendly cooperative relationship with both North Korea and South Korea," he said.

Asked whether the lack of a meeting between Xi and Choe showed China's unhappiness with its old ally North Korea, Hong said: "As for your supposition, this is incorrect".

He did not elaborate.

Chinese media said Choe and his delegation left for home the same day they arrived.

Park's sixth summit meeting with Xi highlighted the growing ties between China and US ally South Korea, as China has become increasingly frustrated with North Korea, in particular its nuclear ambitions, its rejection of talks and its threats to unleash war on its enemies.

Despite the frustration, China remains North Korea's sole significant backer.

North and South Korea averted a full-on military confrontation last month and reached an agreement to improve ties following a rare exchange of artillery fire over their heavily fortified border.

China wants previous agreements reached during so-called six-party talks with North Korea - which include the United States, Japan, Russia and South Korea - to be fulfilled, along with relevant U.N. resolutions.

Numerous efforts to restart the talks since they were last held more than six years ago have failed.

China, North Korea's sole major ally, backed it in the 1950-53 Korean War, with late leader Mao Zedong's eldest son dying in the conflict with the South and its allies.

China, the world's largest exporter, is now South Korea's biggest trading partner. South Korea is one of the few developed countries that runs a surplus with China.