The Standing Committee of the National People's Congress, the nation's top legislature, started to review the draft law on safeguarding national security in the Hong Kong Special Administrative Region on Thursday.

The draft specifies four types of criminal acts and stipulates relevant criminal responsibilities. The four types of crimes are secession, subversion of State power, terrorist activity and collusion with foreign forces that endanger national security.

The draft was submitted for deliberation to the 19th session of the Standing Committee of the 13th NPC, which opened on Thursday.

The NPC approved a decision on May 28 during its annual session in Beijing to improve the legal system and enforcement mechanisms for Hong Kong.

The decision authorized the NPC Standing Committee to draft the law.

The legislation came after continuous unrest in Hong Kong starting last June, triggered by a now-withdrawn bill to amend the SAR's extradition law. The chaos saw a number of cases of vandalism and attacks, making national security risks in Hong Kong a prominent problem, legislator Wang Chen said in May.

Although Article 23 of the Basic Law stipulates the SAR shall enact national security laws on its own, the SAR's legislature has failed to introduce such laws since Hong Kong's return to China in 1997.

On Wednesday, foreign ministers from the Group of Seven countries issued a joint statement urging China to reconsider the national security legislation planned for Hong Kong, claiming that the decision is not in conformity with the Hong Kong Basic Law, the region's mini-constitution, and would risk undermining the "one country, two systems" principle and the region's autonomy.

Foreign Ministry spokesman Zhao Lijian said on Thursday that China expressed strong indignation and opposition to the G-7 statement.

He said China is determined to advance the national security legislation for Hong Kong, and urged the G-7 nations to stop interfering in Hong Kong affairs.

"We urge relevant parties to study the Constitution of the People's Republic of China and the Hong Kong SAR Basic Law and view the national security legislation in an objective manner," he said.

The central government listened to views concerning the legislation on June 3 from a delegation from Hong Kong led by Chief Executive Carrie Lam Cheng Yuet-ngor.

Hong Kong Secretary for Justice Teresa Cheng Yeuk-wah said she believes the NPC Standing Committee will take into account Hong Kong people's opinions and concerns.

Cheng said the legislation is to protect the rights and freedoms of Hong Kong people and safeguard the city's long-term prosperity under the "one country, two systems" principle.

Zhou Jin contributed to this story.