The U.S. ambassador returned to work in Libya on Thursday, raising the U.S. flag over a re-opened embassy, a month after Muammar Gadhafi was driven from power with the help of a NATO-led bombing campaign.
Gene Cretz pledged support for Libya's transitional government and said he expected the last Gadhafi loyalists to lay down their arms imminently.
Also Thursday, Tunisia's Interior Ministry said Libya's former prime minister under Gadhafi, Al-Baghdadi al-Mahmoud, had been arrested overnight.
He was captured in the southern town of Tameghza, near Tunisia's border with Algeria, according to ministry spokesman Hichem Meddeb.
The forces of the interim Transitional National Council (TNC) are confronting stiff resistance in the last strongholds of Gadhafi loyalists within Libya, and the provisional leadership faces questions about whether it can unify a country divided on tribal and local lines.
Seeking to bolster Libya's new leaders, President Barack Obama said this week Cretz would return to Tripoli and "the American flag that was lowered before our embassy was attacked will be raised again."
The embassy building was ransacked by a mob of Gadhafi supporters before Tripoli was taken over by forces loyal to the new government.
"I think it is a matter of time before Gadhafi and his remaining loyalists, their resistance is finished," Cretz told reporters at a ceremony to mark the re-opening of the U.S. mission.
The White House felt vindicated in its approach to Libya when rebel forces took Tripoli late last month.
It had faced criticism for an initially slow response to the Libyan uprising and then set strict limits on the U.S. role in the NATO air assault, which was officially described as a means of stopping the massacre of civilians.
Obama this week met Mustafa Abdul Jalil, chairman of Libya's National Transitional Council (NTC) when he and interim Prime Minister Mahmoud Jibril came to the United States for the United Nations General Assembly.
The U.S. president held out promise the United States would build new partnerships with Libya, a top oil producer.
Cretz praised the NTC for its efforts to date, but said the formation of new institutions may be drawn out, as regional tensions and frictions between Islamists and those who envision a secular state come to the fore in a new Libyan politics.
"These are splits and fractures in the body politic that are a result of 42 years of mismanagement by Muammar Gadhafi," Cretz said. "There is an East-West problem, the problem of the old regime versus the new regime, the problem of the potential challenge of the Islamists."
"I expect when Mr. Abdel Jalil and Mr. Jibril come from their journey to the U.N., the process will begin in earnest. But it will take what it takes."