SANAA, Yemen — Shiite rebels and Sunni militiamen battled in the streets of the Yemeni capital for a second day Friday in fighting that has killed at least 120 people, driven thousands from their homes and virtually shut down the country's main airport. The battles are raising fears of greater sectarian conflict, unseen for decades in Yemen.
Yemen has been chronically unstable for years. But its main fight has been by the government against al-Qaida militants who operate in the south and the mountainous center of the country.
In the past few months, however, the Shiite rebels known as the Hawthis have become one of the country's most powerful players. They surged from their stronghold in the north, taking a string of cities and have fought to the capital, Sanaa.
Their main opponent has been Sunni Muslim hardliners — militias and army units allied with the Islah party, which is the Muslim Brotherhood's branch in Yemen, or tribal fighters sympathetic with the Brotherhood or al-Qaida. The government of President Abed Rabbo Mansour Hadi, an ally of the United States, appears largely caught in the middle between the two forces.
After taking control of the Sanaa suburb of Shamlan this week, Hawthi fighters on Thursday launched an assault on the Sunni hardliners' stronghold, Iman University, which is seen as a breeding ground for militants. On Friday, the Hawthis attacked the nearby headquarters of state TV, trying to storm the building, which the night before they hit with mortars, witnesses said.
"Every minute, there is something rattling or bombing, either rocket-propelled grenades or machine guns. The wall hangings fell down. The house was shaking with every explosion," Ammar Ahmed, who lives near the university, said of fighting overnight.
Army units joined Islah gunmen in fighting the rebels. Bloodied bodies lay in the streets next the charred vehicles in front of the university, said another resident of the area, Ahmed Ibrahim. Hawthis tried to take a hill overlooking the university but were driven back by artillery fire, witnesses said.
Fighting also spread to the Massbah district, where Hawthis targeted house of Gen. Ali Mohsen al-Ahmar, an ally of the Islamists who led the military against the Hawthi rebellion in the north from 2004 to 2010.
At least 120 people, predominantly fighters from either side, were killed over the past 24 hours, according to medical officials, who spoke on condition of anonymity because they were not authorized to speak to the press.
Troops at a key intersection prevented the Hawthis from approaching the airport, north of the capital. However, the civil aviation agency said most foreign airlines had suspended flights to Sanaa for 24 hours because of the security situation.
The fighting is the latest chapter of Yemen's turmoil. The impoverished Arabian nation has long faced the threat from al-Qaida in the Arabian Peninsula, which is considered one of the most dangerous branches of the terror network. The U.S. has been working with the government for years to fight the militants, who at one point in 2011 took over several southern cities until they were driven out the following year.
Yemen has also faced a persistent separatist movement in the south, which was an independent nation until 1990. Across its territory, the country also has deep tribal divisions.
It went through political upheaval starting in 2011, when Arab Spring-style protests erupted against longtime autocratic President Ali Abdullah Saleh. After months of clinging to power, Saleh was eventually forced out, and Hadi was brought in to replace him. Still, Saleh's loyalists permeate the government and military and are accused of trying to undermine Hadi.
Hadi has been trying to lead widescale reforms to reshape and decentralize Yemen's political system by creating six regions that would be given greater powers to satisfy the various divisions in the country.
Throughout, the sectarian Sunni-Shiite divide has rarely been in the forefront of the country's tensions — in sharp contrast to Syria and Iraq, which have been torn apart by hatreds between the two communities, stoked by by the regional rivalry between Sunni powerhouse Saudi Arabia and Shiite power Iran.
The version of Shiism prevalent in Yemen, Zaydi Shiism, is considered close to Sunni Islam, and the communities have long been intertwined in the country's power structure with little distinction. Zaydis are believed to make up just under half the population of 35 million people.
However, hardliners on both sides could change that. The Hawthis first emerged in the 1990s as a movement pushing to revive the Zaydi identity. Its opponents believe it wants to reestablish a Zaydi religious state in the north that existed until the 1960s, under the rule of an "imam," or spiritual leader. They also accuse it of becoming an ally of Iran to further its influence in the country, a claim the movement denies.
On the other side, many Sunni hardliners who are prevalent in parts of the military, in armed militias as well as al-Qaida consider Shiites as heretics.
From 2004, the Hawthis fought a series of civil wars, but the fighting was largely contained to the area around its main stronghold in the north, Saada. Often in the fighting, the Yemeni military called up Sunni militias to help it against the Shiites. The last war ended with a 2010 ceasefire, but during the political turmoil of the anti-Saleh uprising, the Hawthis took total control of the Saada region.
In past weeks, they have surged south, taking a string of towns and cities. The Islamist hardliners they were fighting are also rivals of the president, Hadi, so he largely turned a blind eye or implicitly backed the Hawthis' advances.
But then the Hawthis launched a protest campaign in Sanaa, setting up sit-in encampments in several parts of the capital. They tapped into discontent with Hadi's government, which earlier this year lifted fuel subsidies, sparking a leap in gas prices, and has been widely criticized as too slow in bringing political and economic change.
The movement denies it wants to take power — and denies any link to Iran. Instead, it depicts itself as a political force seeking reform. Its opponents, however, are skeptical.
Saudi Arabia, which wields powerful influence in Yemen, also initially appeared to be happy to see the Hawthis battle the Muslim Brotherhood, which the kingdom views as a bitter enemy. But now Saudis have raised fears over the rebels' advance on Sanaa.
In a recent editorial in the Saudi-owned Asharq al-Awsat newspaper, Saudi writer Tareq al-Homayed called the Hawthis a tool of Iran to spread its influence. He warned that the Hawthis could capture Sanaa at any time and said Saudi Arabia must have a plan to ensure that "all of Yemen does not fall into the hands of the Hawthis and Iran."
Michael reported from Cairo.