People protest for human rights and democracy in Vietnam outside the White House during the visit of General Secretary Nguyen Phu Trong of Vietnam, in Washington DC, USA, 07 July 2015. Obama met with the Vietnam's Communist Party leader to discuss strengthening ties. EPA/MICHAEL REYNOLDS

President Obama met with Vietnam's Communist Party leader at the White House on Tuesday and pledged to make his first visit that nation "sometime in the future."

It was not immediately clear when Obama would make that visit, although some foreign policy analysts have speculated the president could make the stop during a broader tour of Asia in November. A senior administration official said later that the White House had no specific travel plans to announce.

Obama and Nguyen Phu Trong met in the Oval Office just before noon and discussed a range of issues, including a 12-nation Pacific Rim trade deal, security issues in the South China Sea and human rights. It marked the first visit from Vietnam's Communist Party leader to the White House since the two nations normalized relations two decades ago.

[Obama working to make Vietnam an ally in dealing with China’s rise]

“This was an excellent opportunity for us to deepen our discussions around our vision for a comprehensive partnership,” Obama told reporters after the meeting.

He called Trong's invitation to visit Vietnam “indicative of the remarkable progress that’s taken place in the relationship between our two countries over the last 20 years” and noted the “difficult history” between the United States and Vietnam.

Obama said that differences remain on human rights and freedom of religion. Vietnamese-American groups demonstrated outside the White House ahead of the meeting, denouncing Vietnam's lack of democracy.

"But what I’m confident about is that diplomatic dialogue and practical steps taken together will benefit both countries, that these tensions can be resolved in an effective fashion," he said.

Trong, 71, noted the historic nature of his meeting and described their meeting as “constructive and candid," including their discussion on the 12-nation Trans-Pacific Partnership trade accord. Obama has made that trade pact a top priority in his second term, despite objections from labor unions about low labor standards in Vietnam and other countries involved in the negotiations.

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U.S. officials have sought to elevate the bilateral relationship with Vietnam at a time when China has asserted its military and economic muscle throughout Southeast Asia. Vietnamese leaders have grown alarmed by Beijing's maritime operations in the South China Sea, a crucial shipping corridor.

Trong said he and Obama “shared their concerns” about South China Sea activities “not in accordance with international law that may complicate the situation.” But neither he nor Obama mentioned China specifically.

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