BEIRUT — Rebels in southern Syria freed 21 U.N. peacekeepers on Saturday after holding them hostage for four days, driving them to the border with Jordan after accusations from Western officials that the little-known group had tarnished the image of those fighting to topple President Bashar Assad.

The abduction and the tortured negotiations that ended it highlight the disorganization of the rebel movement, which has hindered its ability to fight Assad and complicates vows by the U.S. and others to provide assistance.

It also has raised concerns about the future of U.N. operations in the area. The Filipino peacekeepers were abducted on Wednesday by one of the rebel groups operating in southern Syria near the Jordanian border and the Israeli-occupied Golan Heights, where a U.N. force has patrolled a cease-fire line between Israel and Syria for nearly four decades.

Activists associated with the group, the Yarmouk Martyrs Brigade, gave different reasons for seizing the 21 men. First they demanded that all government forces leave the area. Then they suggested the peacekeepers were human shields against government attacks. Then they declared them “honored guests” held for their own safety.

They also released videos online, including one on Saturday of a bearded rebel commander with his arms around two peacekeepers’ shoulders, flashing a V for victory sign.

On Saturday, after negotiations that the top U.N. official in Damascus described as “long and difficult,” the rebels changed the plan to deliver the peacekeepers to a U.N. team, instead taking them to the Jordanian border.

Video broadcast by Arab satellite channels late Saturday showed them sitting at a round conference table in Amman, their bright blue helmets in front of them.

U.N. Secretary-General Ban Ki-moon welcomed their release and called on all parties in Syria to respect the peacekeepers’ freedom of movement.

It was the first time in nearly two years of violence in Syria that U.N. personnel have been directly caught up in the civil war, which evolved from an uprising against Assad that broke out in March 2011 and has left more than 70,000 people dead.

Since then, hundreds of independent rebel groups have formed across the country to fight Assad’s forces, overrunning military bases and seizing territory in northern and eastern Syria while the regime maintains its grip in the center and the capital, Damascus.

Although some groups have banded together into organized brigades, most still operate independently, competing with each other for resources and booty from captured sites.

Even the rebel’s political leadership, the Syrian National Coalition, which the U.S. and other powers have officially recognized, has no direct control over fighters on the ground. And it remains unclear how many rebels follow its associated High Military Command, which was formed in Turkey in December.

This lack of a central command has hindered rebel efforts against government forces and discouraged the U.S. and others from providing arms.

Last month, the U.S. promised $60 million dollars in new aid for the opposition but refused to arm the rebels, saying more weapons would worsen the situation and could help extremists.

The release of the 21 peacekeepers serves as a case study in rebel disorganization.

As the days passed and the captors’ terms changed, international indignation rose.

State Department spokeswoman Victoria Nuland blasted the Syrian government on Friday for shelling the area, while also warning the rebels that the kidnapping was “not good for their reputation and that they need to immediately release these people.”

The men were held in the village of Jamlah, less than two kilometers (a mile) from the Jordanian border.

A U.N. team tried to retrieve the hostages on Friday, but abandoned the plan because of government shelling.

On Saturday, another U.N. team reached the area and stopped in a village less than a mile away to wait for the captives, said Mokhtar Lamani, the U.N.-Arab League envoy to Syria.

Lamani said the team was “surprised” when the rebels issued a “very urgent request” that the team come to the village itself.

The team demurred, Lamani said, then was “surprised” again when rebels took the peacekeepers directly to Jordan.

“We were surprised to hear to hear the news from a satellite channel that they had reached Jordan,” he said. “Praise God in the end that all of them were released safely.”

An activist associated with the captors said via Skype that the rebels had not been able to reach the U.N. team because of “security conditions” so had taken them to Jordan instead.

He said the Syrian government had been shelling and carrying out airstrikes on the area for weeks, and that locals worried the situation would get worse after the captives left.

“They lightened the shelling today, but we fear that now they will launch a harsh attack on the area,” he said, speaking on condition of anonymity out of fear of reprisals.

The Syrian Foreign Ministry said in a letter to the United Nations Saturday that the Syrian army had held its fire in the area “out of concern for the security and safety of the U.N. forces.”

It called on the U.N. to “unequivocally condemn the attacks of those terrorist groups against civilians and work to dislodge those terrorist groups immediately from the region.”

The Syria government says the uprising is a foreign-backed conspiracy to weaken the country carried out by “terrorists” — its blanket term for the opposition.

The peacekeepers are part of a U.N. mission known as UNDOF that was set up to monitor a cease-fire in 1974, seven years after Israel captured the plateau and a year after it pushed back Syrian troops trying to recapture the territory.

The truce’s stability has been shaken in recent months, as Syrian mortar shells have hit the Israeli-controlled Golan Heights.

Israeli officials worry the violence will prompt UNDOF to end its mission.

On Friday, U.N. spokesman Martin Nesirky said “the mission in the Golan needs to review its security arrangements and it has been doing that.”