HANOI, Vietnam (AP) — Cambodian Prime Minister Hun Manet met with his Vietnamese counterpart on Monday on an official visit to boost relations between the neighboring Southeast Asian countries that are close but historically complicated.

Vietnamese Prime Minister Pham Minh Chinh and Hun Manet attended a welcome ceremony in the capital, Hanoi, where they reviewed an honor guard before holding talks that Cambodian officials had said would cover cooperation in the fields of education, trade, security, defense and border affairs, among others.

The two leaders also witnessed the signing of several agreements on cooperation in trade and science.

Two-way trade between Vietnam and Cambodia totaled $10.57 billion in 2022 and $7.1 billion in the first 10 months of 2023, with a projection to reach $9 billion by the end of the year, according to the state Vietnam News Agency. Vietnam is Cambodia’s third-largest trading partner.

Hun Manet was also scheduled to meet with Nguyen Phu Trong, who as general secretary of the Communist Party of Vietnam is the country’s top leader; Vo Van Thuong, the president; and Vuong Dinh Hue, the National Assembly chief.

It is Hun Manet’s first visit to Vietnam since he became prime minister in August, succeeding his father Hun Sen, who maintained close relations with Vietnam’s communist leadership during his 38 years in power.

Many Cambodians, however, harbor a traditional hostility toward bigger and richer Vietnam, which they suspect of seeking to annex Cambodian territory. Some Cambodian politicians highlight the issue, and prejudice against ethnic Vietnamese residents is not rare.

Hun Manet’s father, Hun Sen, was installed as prime minister in 1985 by a Vietnamese occupying force that had invaded Cambodia to oust the communist Khmer Rouge from power in 1979. The extremist policies of the Khmer Rouge are held responsible for the deaths of an estimated 1.7 million Cambodians through starvation, overwork and execution.

Hun Sen had served as a middle-ranking Khmer Rouge commander, losing an eye in combat during Cambodia’s 1970-75 civil war. He fled to Vietnam in 1977 — as the Khmer Rouge were carrying out purges among its own cadres — and joined an anti-Khmer Rouge resistance movement established there.

Hun Manet in 1999 became the first Cambodian to graduate from the U.S. Military Academy at West Point. Before becoming prime minister, he was commander of Cambodia’s army.

However, he shows no signs of deviating from his father’s policies, under which China is Cambodia’s most important ally. China in recent years has increased its influence throughout Southeast Asia.

China’s leader Xi Jinping is scheduled to make a state visit to Vietnam on Tuesday and Wednesday. It was not announced if he would also meet Hun Manet, whose own visit extends until Tuesday.