Rebel fighters have reportedly taken over the Libyan capital of Tripoli, and NATO is saying that the rule of Moammer Gadhafi is "crumbling." The Libyian rebels say that they have captured Seif al Islam Gadhafi and have surrounded the Gadhafi compound. "Tonight it's over," said Mohamad al Akari, a Transitional National Council advisor. And Reuters has Tweeted, "Gadhafi prepared to negotiate directly with head of rebel transitional council: spokesman." [Updates Below]

However, the rebels have given their own conditions for negotiations: "Head of Libya rebel council says ready to stop fighting on condition Gadhafi announces departure: report," Reuters Tweeted. Earlier in the day, Gadhafi, who has ruled over Libya for 42 years, vowed to fight on, and called on his supporters to help him protect the city: "We will fight to the last drop of blood. We will never give up."

"It's a very fluid situation. We can see that the regime is crumbling, and the sooner Gadhafi realizes he cannot win this war against his own people, the better," said NATO spokeswoman Oana Lungescu. "He's the one who's responsible for starting the conflict and he should spare his people further bloodshed."

President Obama has been getting frequent updates on the Libya situation all day. And according to Washington Times reporter Emily Miller, "Hmm... Obama stopped golf after about 9 holes. Last time that happened, the Seals killed Osama bin Laden."

Update 6:05 p.m.: Gaddafi has now repeated his earlier calls for Libyans to "save Tripoli" in speech on state TV, Reuters reports. According to Al Jazeera, three of Gadhafi's sons have now been captured by rebels, including one who voluntarily surrendered.

In addition, according to reports from Al Arabiya, "Gadhafi men are dumping their military uniforms so they wouldn't be identified."

Update 6:35 p.m.: Al Jazeera is reporting that they are expecting a video message from Saif Al Islam Gadhafi soon. A Rebel press conference has been called for 2 a.m. in Benghazi. Adding more credebility to the uprising, the Libyan Embassy in Algeria announced its loyalty to the Libyan Revolutionaries.

You can check out photographs of the rebels as they closed in on Tripoli here, and video of the rebels (as well as more updates) here at Reuters. Below, you can watch a terrifying video of a Libyan state television presenter holding a gun, and saying (it's not translated) she and other staffers are ready to become martyrs to defend the station as anti-Gaddafi forces close in on Tripoli.