American aid worker Jeff Woodke, who had been held captive in Africa since 2016, was freed Monday, according to National Security Advisor Jake Sullivan.

Sullivan expressed his gratitude and relief at the release of American hostage Jeff Woodke after he had been held captive for more than six years, per Fox News.

"The U.S. thanks Niger for its help in bringing him home to all who miss & love him," Sullivan said, thanking everyone in the government who have worked toward Woodke's release.

Woodke was kidnapped in October 2016 from his residence in Abalak, Niger, by men who brutally murdered his guards before forcing him into their truck and driving north toward Mali's border.

During a media briefing on Woodke's release on Monday, a senior Biden administration official referred to the event as the culmination of years of work. However, he did not elaborate on the circumstances that led to his release or his current whereabouts.

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American Aid Worker Jeff Woodke Was Released Without Condition

Until recently, it was believed that Jeff Woodke had been kidnapped by JNIM, a West African affiliate of al-Qaeda, and was being imprisoned in Africa's vast Sahel region, said USA TODAY.

For more than six years, the United States military led a multi-agency operation that included law enforcement and the intelligence community, as well as support from French officials, to locate Woodke and secure his release, said John Kirby, spokesman for the National Security Council.

When he traveled to Niger last week, Secretary of State Antony Blinken reportedly had meetings with authorities over Woodke's abduction, Kirby added.

Kirby also emphasized that no ransom was given to Woodke's captors and that no compromises were made and insisted that no exchange of prisoners was necessary to guarantee his release.

Woodke worked in Niger as a humanitarian relief worker for almost 30 years.

Similarly, French journalist Olivier Dubois, who had been held captive for over two years, was released on the same day. When asked how his release was ensured, the French government remained silent.

Jeff Woodke Was the Second American to Be Freed in Six Months

Until the release of a French woman and two Italian men in Mali in October 2020, Jeff Woodke and Debois were the most high-profile foreigners known to be imprisoned in the region, Yahoo! News noted.

Emmanuel Macron, the French president, posted on Tuesday that he and Dubois had spoken on Monday.

"Immense relief for the nation, for his relatives and fellow journalists," Macron tweeted. "Deep gratitude to Niger for this release."

Laith Alkhouri, CEO of Intelonyx Intelligence Consulting, speculated that Blinken's visit to Niger and promise of millions of dollars in aid might not be a coincidence even though the exact circumstances surrounding the releases remained unknown.

Their release could have been negotiated with the help of the Niger government's intelligence apparatus, Alkhouri claimed.

It was brought up during Blinken's visit to Niamey last week, and a senior U.S. administration official, commenting on condition of anonymity, confirmed that the American aid worker, Jeff Woodke, was the second American to be freed in the past six months.

Two Red Cross workers were released in Mali, the International Committee for the Red Cross reported on Monday.

However, the company refused to comment on the identities of the abducted workers or the details surrounding their kidnapping; it was also unclear whether they were connected to the other hostages who were eventually freed.

Furthermore, no information on the second hostage freed in Niger has been released.

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Written by: Bert Hoover

WATCH: Kidnapped American aid worker Jeffrey Woodke has been freed from Niger - From USA TODAY