VIENTIANE, Laos » Acknowledging the “challenging history,” President Barack Obama on Tuesday opened a historic visit to this isolated Southeast Asian nation on a mission to heal war wounds and reinvigorate relations with a country with rising strategic importance to the U.S.

Greeted by a military band, traditional dancers and a warm, tropical rain, Obama told Lao President Bounnhang Vorachit he hoped to forge a partnership that would “make our two countries whole again” and promised a new era would “mean greater progress and opportunity for the people of Laos.”

Obama is the first sitting U.S. president to set foot in the impoverished, landlocked country, where for nine years the U.S. conducted a punishing, covert bombing campaign in an effort to cut off communist forces in neighboring Vietnam. The bombardment left behind deep scars, millions of unexploded cluster bombs across the countryside and decades-worth of cleanup.

As a first sign of the new relationship, the Obama administration announced Tuesday it was committed $90 million over the three years to clearing the unexploded ordnance. The U.S. has contributed $100 million to the effort in the last 20 years, as annual deaths have fallen from more than 300 to fewer than 50, the White House said.

The Lao government said it would increase efforts to recover remains and account for Americans missing since the Vietnam War.

Obama is one of several world leaders arriving for a meeting of the Association of Southeast Asian Nations. Taking its turn as the chair of the regional forum, the Laos’ communist government is using the moment to seize the spotlight.

For Obama, the visit is a capstone to his years-long effort to bolster relations with Southeast Asian countries long overlooked by the United States. The outreach is a core element of Obama’s attempt to focus U.S. policy on Asia in order to counter China’s dominance in the region and ensure a foothold in growing markets.

Obama was slated to tout his so-called Asia pivot policy and his legacy in the region in a speech later Tuesday.

But Obama’s outreach to those regional powers hit a snag just as he arrived in the region from China. The White House called off a planned meeting Tuesday with Philippine President Rodrigo Duterte, after the brash new leader referred to Obama as a “son of a bitch.”

Duterte, who had been expecting Obama to criticize his deadly, extrajudicial crackdown on drug dealers, later said he regretted the personal attack on the president.

In a statement read out Tuesday by his spokesman, Duterte said his “strong comments” to certain questions by a reporter “elicited concern and distress.”

“We look forward to ironing out differences arising out of national priorities and perceptions, and working in mutually responsible ways for both countries,” the statement said.