President Obama will welcome Nguyen Phu Trong, the general secretary of Vietnam's Communist Party, to the White House Tuesday.

The historic meeting, which comes roughly four decades after the fall of Saigon, marks the 20th anniversary of normalized relations between the U.S. and Vietnam. It also aims to strengthen ties between the two nations, according to the White House.

"The President also welcomes the opportunity to discuss other issues, including the Trans-Pacific Partnership, human rights, and bilateral defense cooperation," the White House said in a statement.

The 71-year-old Trong wrote to western journalists Friday that "like in any relations between two countries in the world, Vietnam and the U.S. have differences on a number of issues such as perception on democracy, human rights and trade," adding that he believes "the most effective way would be open and constructive dialogues to better understand each other so that differences won't become hurdles to the overall bilateral relations."

Last month, Defense Secretary Ashton Carter met with Trong at the Presidential Palace in Hanoi.

The meeting with Trong comes days after Obama announced diplomatic relations with Cuba — another Communist-led country with which the U.S. has sparred with — would be formally resumed.

Trong has led the Communist Party of Vietnam since 2011. He also heads the party's Secretariat and the party's Central Military Commission.