Vietnam on Thursday began a two-day state funeral service to bid farewell to Nguyen Phu Trong, 80, the leader of its ruling Communist Party who died a week earlier.

Amid tight security, hundreds of people took to the streets of Hanoi around a downtown funeral house and went to his family home outside the capital to pay their last respects to the Southeast Asian country's once most powerful man.

State officials and foreign dignitaries, including European Union foreign policy chief Josep Borrell, President of the Cuban National Assembly Esteban Lazo Hernandez, South Korean Prime Minister Han Duck Soo, Cambodia's former prime minister Hun Sen, President of the Australian Senate Sue Lines, were seen attending the funeral.

Other foreign dignitaries, including U.S. Secretary of State Antony Blinken, China's top political advisor Wang Huning and Indian security advisor Ajit Doval are also expected to be in Hanoi during or after the funeral to bid farewell to Trong.

"My infinite condolences to Comrade General Secretary Nguyen Phu Trong, an exceptional leader, a steadfast communist party member, a shining example of constantly studying and following Ho Chi Minh's ideology," Vietnam's President To Lam, who has temporarily taken over Trong's duties, wrote in the funeral book, referring to modern Vietnam founding father.

No public entertainment was allowed and flags at offices and other public places are being flown at half-mast during the two-day period.

"He devoted his life to the people and the nation, and I thanked him for that and wish to say good buy to him," said Hanoi resident Nguyen Thi Minh Thu, 68, while she queued in front of the funeral home on Thursday.

Cuba and Laos, Vietnam's communist friends, have also held state funeral for the Vietnamese leader.

During Trong's time as party head, Vietnam recorded an average annual economic growth of 5.79%, one of the fastest in Asia.

In 2017 he unleashed what many saw as a China-style crackdown on corruption, known as "blazing furnace", under which hundreds of senior officials were investigated for graft and many forced to quit, including cabinet ministers, a parliament chairman and two state presidents.

Trong also led Vietnam to boost its relations with global powers, including the United States and China, as part of its "bamboo diplomacy", as the country tried to navigate rising global disputes and maintain economic growth.