Referring to the events in Libya, US Senator John McCain has termed the public appearance of Muammar Gaddafi's son a "little PR coup".

Muammar's son Saif - whom the rebels claimed yesterday to have captured - turned up outside his father's compound, alive and well, wearing battle fatigues and flashing a Victory sign.

Speaking on CBS's "The Early Show, McCain said that, despite Saif al-Islam Gaddafi's "little PR coup," there's an "inevitability" about Gaddafi's downfall. "How long it takes and how long he holds out, I can't tell you exactly.

"It could be difficult, because use of air power to a large degree is negated when you get into this kind of urban warfare, and it's hard to identify targets, and hard to be effective," he told anchor Erica Hill. "But I don't think there's any doubt of the eventual outcome.

He further insisted that hundreds, perhaps thousands of political prisoners being held in Libyan jails had to be released.

McCain also said it was important to free the hundreds, perhaps thousands of political prisoners being held in Libyan jails.

In another interview for Fox News, the former US presidential candidate said that the situation in Libya should be a warning for Russian leadership.

"Places like China and Russia and other places, they are very uneasy. This is about people aspiring for freedom. And that's what the Libyan people have just achieved," the Republican Senator declared.

According to McCain, the one to go after Muammar Gaddafi would be Syrian President Bashar Assad, who would have to give up power.

McCain also expressed his firm belief that the Arab Spring movement would continue to spread, suggesting that it was no accident that demonstrations in Syria had recently intensified.