Eighteen months after the downfall of Moammar Gadhafi, Libya remains a powder keg with a government unable to control dozens of armed groups whose lawless marauding has created a security crisis that's driving off desperately needed foreign investment.

The energy-rich North African state is in a constant state of uproar and anxiety, riven by ideological, religious and tribal rivalries.

Egypt and Tunisia, where pro-democracy uprisings overthrew longtime dictators earlier in 2011, are also in turmoil but Libya is armed and dangerous and if it explodes the entire region will be dragged deeper into chaos.

"The nation is in essence split up into three, or even possibly four, regions, and the state seems to lack the ability or support for uniting them into a national unit," observed Saudi Arabian security affairs analyst Nawaf Obaid.

"At present, the survivability of Libya in its present form over the next decade is highly in doubt," said Obaid, who's close to Saudi Arabia's ruling family.

In eastern Libya, the Benghazi Regional Council is the primary power. Benghazi and Deraa, another eastern city, were long jihadist strongholds that opposed the dictatorial Gadhafi when he was in power.

Deraa, in particular, is notorious for the number of jihadists that migrated from there to join the conflicts in Iraq and more recently Syria, as well as the manpower it's provided for Islamists who fought Gadhafi and the seizure of northern Mali by al-Qaida.

Benghazi city is a major flash point, as evidenced by the Sept. 11, 2012, killing of U.S. Ambassador Christopher Stevens and three other Americans in an attack on the U.S. consulate, widely blamed on al-Qaida or its local affiliate, Ansar al-Sharia.

On Monday, a car bomb exploded outside the city's main hospital, killing at least 15 people and wounding dozens.

It was the latest in a long line of mysterious bombings targeting security forces and foreign diplomatic missions in a city that was the wellspring of the uprising against Gadhafi in February 2011.

In Tripoli, heavily armed gunmen ended a two-week siege of the foreign and justice ministries Saturday after the government agreed to pass a law banning anyone who held senior positions in Gadhafi's regime from holding office in the new administration, a move many say will impede political progress.

Despite historic elections in July 2012, Obaid said Tripoli has failed "to unite its fighting factions into a single nation-state, contain the armed forces in an attempt to achieve international parity, or engage in any state-building efforts to expand the nation-state and its institutions to create respectable international status.

"Central Authority has been decimated, and the new government is unable to reassert its authority over any significant section of the country," he noted in a March paper for Harvard Kennedy School's Belfer Center.

"The South remains lawless and without political control, plagued by unaddressed violence, narcotics and weapons trafficking."

Security officials say there are about 500 militias and armed groups across Libya, most of them competing with one another. Libya's Warrior Affairs Commission estimates these total around 250,000 men who hold allegiance to warlords, tribal leaders and Salafist groups rather than to the government that's struggling to emerge.

Most Libyans depend on these forces for security, which makes disarming them doubly difficult.

Some 230 of these militias are registered in Algeria's third-largest city, Misurata, alone.

The battle-hardened fighters there have turned the once-thriving commercial and industrial coastal city in western Algeria into a hotbed of militancy that has become a major force in Algerian politics.

The complexities of Libya's tribal system lie at the root of the anarchy.

There are at least 140 tribal networks, each with scores of clans, whose rivalries Gadhafi exploited to stay in power after his 1969 coup.

Ethnic groupings complicate things further. The most important are the Arabs, the Berbers -- which included Gadhafi's tribe, the Gaddafa -- and the Tuareg, who supported Gadhafi and then spread the jihadist war to Mali after he fell.

Al-Qaida played a key role in toppling Gadhafi and remains a potent threat.

Analyst Robert Kaplan of the U.S. global security consultancy Stratfor observed that Libya's oil resources "can internally generate revenue for armed groups and politicians both.

"Thus, Libya will become a metaphor for much of North Africa and the Sahara, places where frontiers are more common than borders."