SANAA, Yemen :Tens of thousands of Yemenis held street protests for and against the government Thursday during an opposition-led "Day of Rage" after President Ali Abdullah Saleh offered to step down in 2013.If Saleh fails to follow through on a range of concessions he made Wednesday to avert unrest, diverse groups could combine forces with mainstream parties to address shared grievances.
Saleh's government faces challenges on several fronts. Following is a list of opposition groups in the Arabian Peninsula state.
OPPOSITION COALITION
The main players in Yemen's opposition coalition, the Joint Meeting Party, are the Islah party (Islamist) and secular Socialists. The umbrella group is also sympathetic to grievances of southerners and Houthis and its protests have been inspired by unrest in Tunisia and Egypt.
Leaders have cautiously welcomed Saleh's offer to step down in 2013, but want to see concrete steps.
Saleh has offered to form a unity government with the opposition, and has promised to delay parliamentary elections to conduct reforms, freeze proposed constitutional amendments on term limits and re-open voter registration.
NORTHERN SHI'ITE REBELS
Yemen's government sealed a truce nearly a year ago with northern Shi'ite rebels to end a six-year civil war that drew in neighboring Saudi Arabia in 2009.
The rebels, known as Houthis after their leader Abdel Malek al-Houthi, belong to the Zaidi sect of Shi'ite Islam and have long complained of discrimination in a country with a Sunni Muslim majority.
Their war against Saleh has displaced around 350,000 people. The shaky truce has largely held despite sporadic clashes between Houthis and pro-government tribes.
SOUTHERN SEPARATISTS
Southern separatists have stepped up their rebellion, with protests and tit-for-tat attacks escalating last year.
Many in the south, home to much of the country's oil and gas reserves, complain northerners have usurped resources while denying them their political rights since north and south united as a single country in 1990.
Saleh's foreign allies have no interest in seeing Yemen break up. Al Qaeda has been most active in areas where separatists also want a state.
DISGRUNTLED YOUTH
Corruption, joblessness and poverty are familiar to the young population. Around 40 percent of Yemen's 23 million people live on $2 a day or less and a third of the population suffers from chronic hunger.
An emerging, more marginalized force of internet-savvy young Yemenis could make more radical demands and pose a bigger threat to Saleh's rule. Many protests center on Sanaa University.
RESURGENT WING OF AL QAEDA
Yemen is trying to quell a resurgent regional wing of al Qaeda that has stepped up attacks on Western and regional targets from Yemen.
Al Qaeda in the Arabian Peninsula claimed responsibility for a 2010 plot to send explosive parcels to the United States, after trying to bomb a U.S.-bound plane in 2009.
Attacks on al Qaeda, including U.S. drone attacks, have stirred up resentment among Yemenis in the areas where al Qaeda is hiding, as the raids have sometimes hurt civilians.
