German Foreign Minister Guido Westerwelle has said Libyan leader Muammar Gaddafi should be brought to court if and when he is captured, local media reported on Tuesday.

"His rule was gruesome, most notably leading a war against his own people," Westerwelle said on Monday.

He added that while Libya was calling for democratic change, "we want the transition to take place in a peaceful, ordered manner."

Speaking in Berlin, Westerwelle stated that assets worth some 7 billion euros (10 billion U.S. dollars) linked to the Gaddafi regime were being frozen by the German government, which would be made available to the new Libyan government once it is in place.

"From the outset, Germany supported a political process: international isolation of and targeted sanctions against the Libyan regime. And this tactic was quite visibly effective," Westerwelle said.

Rebel forces appear to be making decisive advances into the Libyan capital Tripoli. The rebels have claimed control of most of the city.