Former Prime Minister Ali Zeidan has been charged with corruption and the misappropriation of $66 billion of state funds during his 15-month administration. Hazem Turkia/Anadolu Agency/Getty Images

Former Libyan Prime Minister Ali Zeidan fled to Europe in defiance of a travel ban on Wednesday after parliament voted him out of office for failing to stop rebels from independently exporting oil from the country in a challenge to Libya's fragile unity.

The crisis arose when rebels, who have seized three eastern ports since August, loaded crude oil onto a North Korean-flagged tanker at Al-Sidra terminal over the weekend.

The tanker left Al-Sidra on Tuesday. According to varying accounts by government officials, the navy or air force then fired on the vessel, although it was not clear if this happened in Libyan or international waters.

Government spokesman Habib al-Amin told a news conference in Tripoli on Wednesday that the firing failed to disable the tanker, which proceeded eastwards into Egyptian waters. He said Libya had asked Egypt and other countries to help stop the ship.

There was no independent confirmation of the tanker's whereabouts, destination or ownership.

The debacle underlines the impotence of the authorities in Tripoli, whose fledgling army and police force are no match for the armed rebel groups who continue to operate under their own set of laws three years after the fall of strong-man Muammar Gaddafi.

After the tanker escaped, an infuriated parliament voted out Zeidan on Tuesday and named Defense Minister Abdallah al-Thinni as acting prime minister for two weeks. Later that same day, Libya's top prosecutor slapped a travel ban on Zeidan because of his suspected involvement in the embezzlement of public funds.

Western powers, who supported the NATO campaign that came to the aid of anti-Gaddafi rebels in 2011, fear the OPEC member state could slide into greater instability or even break apart, with rival groups laying claim to power and vast oil reserves.

The rebels controlling ports in the east demand autonomy and a greater share of oil resources for their region, which they say was disadvantaged during Gaddafi's 42 years in power.

Led by Ibrahim Jathran, a former anti-Gaddafi fighter, they are drawn from former oil security forces who mutinied last year and took over the oil terminals to press their demands.

Officials said Libya was close to bankruptcy because of the six-month oil blockade, which cost the North African country an estimate $8 billion in lost revenue in 2013, and set a two-week deadline for talks with rebels to end the port seizures before force was used. Similar threats in the past have proved empty.

"We need an emergency budget for the government to carry out its tasks, and to deal with the country's serious security challenges," Thinni told reporters.

After flying out of Libya, Zeidan made a two-hour stopover in Malta before going to "another European country", Maltese Prime Minister Joseph Muscat told state-owned television TVM.

Government sources in Malta said Zeidan had left on a private plane for Germany, but authorities in Germany and other European countries have not confirmed his whereabouts.

Wire services