Former Afghan President Hamid Karzai expressed support for China's efforts to safeguard national unity and security in a meeting with Chinese Ambassador to Afghanistan Wang Yu.

"Hong Kong's affairs are China's internal affairs, and shouldn't be interfered with by any other country," Karzai said during the meeting.

"China's principle of 'one country, two systems' has effectively preserved national unity and promoted Hong Kong's prosperity," the ex-Afghan President said.

"I firmly support China's efforts to safeguard national unity and security," he added.

Karzai later expressed his support for the one-China policy on Twitter, posting, "China's right to protect its national security must be respected."

"All countries should adhere to international law and the basic principle of non-interference in the internal affairs of other countries," he tweeted.

Chinese lawmakers voted overwhelmingly at the 13th National People's Congress (NPC), the country's top legislature, last week to approve a decision on establishing and improving the legal system and enforcement mechanisms for the Hong Kong Special Administrative Region to safeguard national security, Xinhua news agency reported.