Vietnam began a two-day state funeral for late leader Nguyen Phu Trong on Thursday, with China, the United States and the European Union among those sending high-level delegations to mourn his passing.

Trong, general secretary of the Communist Party of Vietnam Central Committee, died on July 19 aged 80 after a period of illness, the Vietnam News Agency reported.

He became general secretary of Vietnam's ruling CPV in 2011 and served as the country's president from 2018 to 2021.

"Respectfully bowing before our heroic comrades, we vow to study, follow the example wholeheartedly and with all our might to serve the Fatherland and serve the people," Vietnamese President To Lam wrote in the condolence book.

Heads of state, leaders of political parties and international organizations sent their condolences on Trong's demise.

China's top political adviser Wang Huning attended the funeral as the special representative of Xi Jinping, general secretary of the Communist Party of China Central Committee.

Attending the funeral are Laotian President Thongloun Sisoulith, Cambodian former prime minister Hun Sen, US Secretary of State Antony Blinken, EU foreign policy chief Joseph Borrell, South Korean Prime Minister Han Duck-soo and former Japanese prime minister Yoshihide Suga, among other foreign dignitaries.

On social media platforms, Vietnamese people posted comments to express their condolences, with many voluntarily changing their profile pictures to black and white.

"I think (Trong) has been the most important leader in Vietnam post-1986 and his legacies are significant," said Le Hong Hiep, a senior fellow at the Vietnam Studies Programme and the Regional Strategic and Political Studies Programme of the ISEAS-Yusof Ishak Institute in Singapore.

'Man of great integrity'

Noting Trong is a man of great integrity, Hiep said his biggest legacy is his leading role in the party's fight against corruption in recent years.

Since 2016, more than 139,000 party members have been disciplined, with eight Politburo members — including former presidents Nguyen Xuan Phuc and Vo Van Thuong — removed from their positions.

For comparison, no Politburo members were ousted for corruption between 1986 and 2016, Hiep said.

Officials handled public affairs with far more caution under Trong as they knew Trong's anti-corruption campaign did not have any limits, said Vu Khang, a doctoral candidate in the Political Science Department at Boston College in the US.

"Vietnam thus has become a better destination for foreign investors," said Khang, adding that the anti-corruption campaign earned the Communist Party of Vietnam much public trust and will continue after Trong's death.

While Trong was not directly involved in managing economic affairs, Hiep said his vision for a socialist-oriented market economy helped promote Vietnam's economic development.

He also noted that Trong used "bamboo diplomacy" to maintain good and balanced ties with all major powers.

The presence of international leaders at Trong's funeral showed their recognition of his contributions to Vietnam's relationship with their countries, he said.

Trong's passing will not affect Vietnam's relationship with China, Hiep said, and he expects the new leadership to continue to promote bilateral ties in the interests of both sides.

"The consensus in Vietnam is that China is an important partner, so it is of paramount importance for Vietnam to maintain a stable and peaceful relationship with China for its own security and economic wellbeing," he said.

The day before Trong's passing, To Lam took over the duties of Trong because of the latter's health condition.

A memorial service was scheduled to take place on Friday before Trong is buried at Hanoi's Mai Dich Cemetery, the final resting place for senior leaders in Vietnam.