Xian is set to become the fifth Chinese city with a direct flight to Pyongyang after Beijing, Shenyang, Shanghai and Chengdu.
North Korea on Tuesday rejected allegations by the top UN human rights official that serious and widespread violations persisted in the country despite its diplomatic opening.
The South Korean news agency said the suspension was likely to affect only major joint exercises, not more routine military training.
Even as experts weighed the implications of Trump's Singapore summit with Kim, the US president struck a typically bullish note in a series of announcements.
US President Donald Trump made a stunning concession to North Korean leader Kim Jong Un on Tuesday about halting military exercises, pulling a surprise at a summit that baffled allies, military officials and lawmakers from his own Republican Party.
Iran warned North Korean leader Kim Jong Un on Tuesday against trusting US President Donald Trump, saying he could cancel their denuclearisation agreement within hours.
Japan's Prime Minister Shinzo Abe on Tuesday welcomed a document signed by North Korea's leader at an unprecedented summit with US President Donald Trump as a "first step" towards denuclearisation.
Kim Jong Un is not believed to have left his hotel since a meeting with Singapore's prime minister, Lee Hsien Loong, soon after his arrival on Sunday in the city-state.
United States President Donald Trump should press Pyongyang to end state-imposed slavery and forced labour, said North Korean defectors ahead of a historic summit between the leaders of both countries.