TRIPOLI, Libya - Rebel fighters stormed into Muammar Gadhafi's compound in central Tripoli on Tuesday after hours of heavy fighting.

Smoke billowed from the compound as the rebels fired their weapons into the air to celebrate.

The storming of the compound marked a fast-moving and sometimes confusing day in Tripoli. Gadhafi's son and heir apparent Saif al-Islam had earler resurfaced free and defiant on Tuesday, thwarting Libyan rebel claims that he had been captured and boasting the government still has control in Tripoli.

Saif al-Islam's sudden - even surreal - arrival at a Tripoli hotel where foreign journalists are staying threw the situation in the capital into confusion just a day after rebels entered the capital with surprising ease.

Rebels say they control most of Tripoli. Rebel spokesman Mohammed Abdel-Rahman, who was in Tripoli, said the "danger is still there" as long as the longtime Libyan leader remains on the run. He warned that pro-Gadhafi brigades are positioned on Tripoli's outskirts and could "be in the middle of the city in half an hour".

China urged Libya on Tuesday to protect its mutually beneficial investments after a rebel warned that Chinese oil companies could lose out after Gadhafi is eventually ousted.

The deputy head of the Ministry of Commerce's trade department, Wen Zhongliang, was responding to a question about remarks made by an official at a rebel-run oil firm, who said Russian and Chinese firms could lose out.

"China's investment in Libya, especially its oil investment, is one aspect of mutual economic cooperation between China and Libya, and this cooperation is in the mutual interest of both the people of China and Libya," Wen told a news conference.

"We hope that after a return to stability, Libya will continue to protect the interests and rights of Chinese investors, and we hope to continue investment and economic cooperation with Libya," Wen said.

Zhao Ruixiong, director of the Board of Directors Office of the Metallurgical Corporation of China Ltd (MCC) said: "We haven't put the recovery of our projects in Libya on the agenda. The situation in Libya remains uncertain. Our business will continue to be suspended until the situation stabilizes."

Jing Ning, first secretary of the Department of West Asian and African Affairs at the Ministry of Commerce, added: "All Chinese investments and contract engineering projects have suspended operations in Libya.

Given the fact that the current situation tends to be brighter in Libya, the Ministry of Commerce is conducting research into the possibility of restoring Chinese projects."

The rebel leadership seemed stunned that Saif al-Islam was free. A spokesman, Sadeq al-Kabir, had no explanation and could not confirm whether Saif al-Islam had escaped rebel custody. But he did confirm that another captured Gadhafi son, Mohammed, had escaped from house arrest. On Monday, the rebels had said Saif al-Islam was captured, but did not give details on where he was held. The Netherlands-based International Criminal Court (ICC) - which indicted Saif al-Islam and his father - had confirmed his capture.

Saif al-Islam, with a full beard and wearing an olive-green T-shirt and camouflage trousers, turned up early on Tuesday at the Rixos hotel, where about 30 foreign journalists are staying in Tripoli under the close watch of government minders.

Riding in a white limousine amid a convoy of armored SUVs, he took reporters on a drive through parts of the city still under the government's control.

"We are going to hit the hottest spots in Tripoli," he vowed. The tour covered mainly the area that was known to still be under the government's control - the district around the Rixos hotel and nearby Bab al-Aziziya, Gadhafi's residential compound and military barracks. The tour went through streets full of armed Gadhafi backers, controlled by roadblocks, and into the Gadhafi stronghold neighborhood Bu Slim.

At Bab al-Aziziya, at least a hundred men were waiting in lines for guns being distributed to volunteers to defend the government. Saif al-Islam shook hands with supporters, beaming and flashing the "V for victory" sign.

"We are here. This is our country. This is our people, and we live here, and we die here," he told AP Television News. "And we are going to win, because the people are with us. That's why were are going to win. Look at them - look at them, in the streets, everywhere!"

Around 75 Chinese companies - 13 of which are State-owned - operated 50 joint projects worth $18.8 billion in Libya before the uprising, according to earlier data from the Ministry of Commerce. Many of those companies are engaged in infrastructure, energy and telecom projects.

As anti-Gadhafi forces rapidly advanced through the capital, journalists staying at the Rixos Hotel suddenly found their freedom of movement sharply restricted by forces loyal to Muammar Gadhafi.

Phoenix TV issued a statement at noon on Tuesday, confirming that three of its journalists, including a television correspondent, a cameraman and a technician had become trapped along with two journalists from China Central Television.