Chinese President Xi Jinping may postpone an upcoming state visit to Japan to deal with a coronavirus outbreak that has killed more than 400 in his country, diplomatic sources said Tuesday.

According to the sources, a preparatory meeting between officials from the countries scheduled for later this month in Beijing and a separate meeting on maritime issues have both been pushed back as China focuses on containing the epidemic.

The delays bode ill for Xi's visit, which had been expected to take place around early April and would entail a summit with Prime Minister Shinzo Abe as well as an audience with Emperor Naruhito and a lavish banquet at the Imperial Palace.

Abe has viewed the visit as emblematic of a recent improvement in Japan-China relations, stressing the importance of stepping up cooperation despite underlying issues including a dispute over Japan-controlled islets in the East China Sea and Beijing's poor human rights record.

But Xi has had his hands full with the pneumonia-causing coronavirus, which has continued to spread in China infecting over 20,500 as of Tuesday night. Authorities have imposed a lockdown in Hubei's provincial capital of Wuhan, where the outbreak originated, and other cities in the province as well as some parts of Zhejiang Province.

On Monday, the Chinese leadership in Beijing admitted "shortcomings and deficiencies" in the response to the outbreak, while Xi called for "prompt and resolute actions" to contain the epidemic.

According to the diplomatic sources, one of the delayed meetings is director-level talks between the foreign ministries and other government agencies of the countries, meant to set the stage for vice ministerial-level talks in Tokyo toward the end of February to work out the details of Xi's visit.

If the vice ministerial-level meeting is also pushed back, "it could have a big impact on the timing of the state visit," one of the sources said.

It also remains to be seen whether Yang Jiechi, China's foreign policy chief and a member of the Communist Party's decision-making Politburo, can fulfill an expected visit later in February as part of the preparations.

"The outbreak is a national crisis for China. Postponement (of Xi's trip) is a possibility," a senior official in Abe's administration said.

The other meeting that has been pushed back regarding maritime issues had been slated to take place next Monday in Ningbo, in eastern China's Zhejiang Province. The sources said other meetings related to Xi's visit have also been rescheduled due to the coronavirus outbreak.

Despite these setbacks, neither country has announced plans to postpone the trip, which would be the first by a Chinese president since Hu Jintao in May 2008.

A China Foreign Ministry spokesperson said Monday both countries should work to ensure Xi's visit goes "smoothly."