BEIJING - China on Monday urged Japan to stick by the three non-nuclear principles, after Japanese officials hinted at allowing the United States to bring in nuclear weapons in emergency.

The three non-nuclear principles state that Japan will not produce, possess or allow the entry into its territory of nuclear weapons. They are an important part of Japan's peaceful post-war development, Foreign Ministry spokeswoman Hua Chunying said.

"They are also significant to regional peace and stability," Hua told a daily news briefing.

Japan may allow the United States to bring nuclear weapons into the country in an emergency that threatens the safety of Japanese citizens,Foreign Minister Fumio Kishida indicated Friday, according to Japanese media reports.

The three non-nuclear principles were first outlined by Prime Minister Eisaku Sato in a speech to the House of Representatives in 1967 and were approved by the parliament in 1971.