Cairo - Even hours after Libya's prime minister was kidnapped Thursday morning, few people knew for sure who had done it or why.

But the mysterious dawn raid on Ali Zeidan's hotel room was a clear demonstration of just how far lawlessness has spread in Libya since the 2011 overthrow of longtime dictator Moammar Gadhafi - and just how powerful the country's militias have become.

The gunmen who swept into Zeidan's hotel room at 4 a.m. and whisked him to captivity in a Tripoli suburb - only to release him unharmed six hours later - had initially claimed to be part of a militia assigned to protect the country's parliament.

A spokesman for the militia, known as the Operations Room of Libya's Revolutionaries, told the Reuters news agency that Zeidan's "arrest" was in response to the government's tacit compliance with the U.S. raid to capture a Libyan al-Qaida suspect in Tripoli on Saturday. The group published an announcement on its Facebook page claiming that Zeidan had been arrested on charges related to corruption.

But the Justice Ministry denied issuing an arrest order. And after Zeidan's release, the militia denied its role in the episode, too.

Zeidan, a human rights lawyer who lived in exile for decades during Gadhafi's rule, has a range of enemies within the government and among Libya's various militias.

Criticism of Zeidan has surged since U.S. forces captured Nazih Abdul-Hamed al-Ruqai, better known as Anas al-Libi, who was wanted in connection with the 1998 bombings of U.S. embassies in Tanzania and Kenya. The Saturday operation was denounced by Libyan officials but still proved deeply embarrassing for the government, which critics accused of being complicit in the operation.

It was not clear whether the kidnapping of Zeidan was connected to a backlash over the U.S. operation.

Geoff Porter, a security analyst for North Africa Risk Consulting, said that al-Libi's capture may have been "a spark" but that Zeidan's kidnapping follows a pattern of political manipulation by armed groups that has worsened under Libya's weak transitional leadership.

"If you have a grievance with the state - and the state is phenomenally unresponsive - one of the ways to compel the state to recognize your grievance is you take an institution or an individual hostage," Porter said. "It was only a matter of time, I think, before someone acted aggressively against Zeidan."

Libya's government is dangerously weak and deeply divided. Its army and police lack power. Day-to-day security efforts are typically delegated to state-affiliated militias that are better armed than the official security bodies, but they are also difficult to control.

In recent months, Libya's myriad - and often competing - militias have used force to try to achieve their political aims. They have shut down oil infrastructure and forced political appointments and legislative changes through the parliament.

Early Thursday, the state news agency quoted an Interior Ministry spokesman as saying that Zeidan had been arrested and was in good health. That report was later contradicted by the interior minister, who called the kidnapping "a crime."

Officials and witnesses said two local militias freed Zeidan - without a fight - from a house in the Tripoli suburb of Fornaj around mid-morning. Zeidan returned to the heavily guarded luxury hotel where he lives, collected his belongings and drove with armed guards to the government headquarters, witnesses said.

At 12:33 p.m. Thursday, as he made his way to his office, Zeidan tweeted from his official account: "If the purpose of my kidnapping is to get me to resign, I won't resign. We are taking slow, but steady steps on the right path."

From his office, he delivered a short speech thanking the military, the police, the militias that helped and those from across the country who "phoned a lot."

Zeidan did not name his captors or detail their demands. But he and government spokespeople suggested that the kidnappers were trying to force him to make political concessions.

"We emphasize that this crime cannot undermine the legitimacy of the Libyan state institutions," a government spokesman said shortly before the prime minister's release. "The interim government emphasizes that it cannot bow to any blackmail from any party."

But the kidnapping was undoubtedly a setback in a country that is trying to change perceptions of lawlessness.

"On the face of it, no matter which way you slice it and dice it, it's obviously a really bad thing when your prime minister is kidnapped," Porter said.