– President Obama is considering broadly expanding weapons sales to Vietnam in a move aimed at strengthening ties with Hanoi and boosting regional defenses against China.

As Obama prepares to visit Vietnam this weekend, U.S. officials said that he is leaning toward a partial lifting — but has not ruled out a full suspension — of the ban on arms sales begun during the U.S. war in Vietnam and eased in 2014.

At the same time, the Vietnamese government is examining a request to grant the U.S. Navy greater access to Cam Ranh Bay, a major supply point for the U.S. military during the Vietnam conflict, and a port with direct access to the increasingly contested islands in the South China Sea.

Obama has not made a final decision, administration officials said. But the changes, if approved, would mark a dramatic upgrade in U.S. relations with an authoritarian communist government that the State Department considers an abuser of human rights.

White House concerns about Vietnam’s lack of progress on civil liberties and political freedoms have held up a decision to end the ban on arms sales — first imposed on North Vietnam in 1964 and later extended to cover the entire country after the U.S.-backed South Vietnamese government fell in 1975.

In the 1990s, President Bill Clinton lifted the trade embargo with an executive order but left in place restrictions imposed by Congress to prohibit sales of weapons and high-technology material. The countries restored diplomatic relations in 1995.

In 2014, Obama eased restrictions on lethal arms sales to Vietnam, with his State Department insisting that the change only affected maritime surveillance and security-related systems.

Obama now is looking at wiping out other parts of the ban, according to senior defense officials and others briefed on the deliberations.

Closer military ties between the two former enemies dovetail with Obama’s steady push since 2011 for a strategic U.S. “rebalance” toward Asia and the Pacific.

In recent months, the administration has refreshed its defense treaty with Japan and has sought congressional support for a 12-nation free trade agreement known as the Trans-Pacific Partnership.

It also has urged China to settle territorial disputes with Vietnam in the South China Sea. The Pentagon has sent warships and surveillance planes close to contested islands where China has built airstrips and other facilities.

Vietnamese officials would like Obama to end the arms ban and allow greater normalization of relations.

Obama administration officials have pushed Vietnam to allow human rights reforms before Obama departs Saturday on a weeklong trip to Vietnam and Japan.