Yemeni officials said Thursday that security forces have gone on high alert, fearing that Al Qaeda members are streaming into the capital, where a Shiite rebel group's demonstrations have turned deadly.

The reports of Al Qaeda infiltration came as the government sought international mediation in reaching a peaceful resolution to its conflict with the Shiite rebel group known as the Hawthis, which clashed with police in the capital Sanaa earlier this week.

Officials fear that Sunni extremists will exploit the state of unrest in Sanaa and attempt to seize government institutions. The country's top intelligence officials convened Thursday to discuss information about possible Al Qaeda attacks, security officials said. The officials spoke on condition of anonymity because they were not authorized to speak to the media.

Thousands of supporters of a Shiite rebel group known as the Hawthis have been holding sit-ins demanding the reinstatement of fuel subsidies and the formation of a new government.

The demonstrations turned deadly earlier this week when at least four people were killed when gunfire broke out as police moved to stop protesters from marching on the prime minister's office. Protesters and police traded blame for the violence, which raised the prospect of a wider conflict.

Presidential adviser Faris al-Saqqaf said a deal between the government and rebels is possible following the United Nations envoy to Yemen's talks with President Abed Rabbo Mansour Hadi and Hawthi leaders. Al-Saqqaf said a deal will be announced within hours. The rebel group's spokesman, however, said that no agreement had been reached and that talks are ongoing.

Al-Saqqaf said the government will appoint a new prime minister and resume fuel subsidies if the Hawthi demonstrators in the capital disperse. Earlier this month Hadi sacked the cabinet, including the prime minister, and partially restored subsidies.

Fuel prices have doubled since Hadi lifted subsidies last month in response to the burgeoning government deficit. Yemen, one of the Arab world's most impoverished nations, has spent nearly $3 billion so far this year on fuel subsidies, roughly 20 percent of the state's expenditures, and $22 billion over the past decade.

The end of fuel subsidies was part of an austerity plan announced earlier this year, which also slashed officials' traveling allowances.  The subsidies have caused a budget deficit of $5 billion, or 13 percent of the country's gross domestic product.

Yemen is struggling with both economic and security challenges, as its military faces Al Qaeda militants, a secessionist movement in the south, and a rebellion in the north.

The U.S. considers Al Qaeda in Yemen to be the most dangerous local branch of the global terror organization because it has been linked to several failed attacks on the U.S. homeland. Washington has launched drone strikes in support of Yemeni government offensives.

The security officials said that a drone strike Thursday killed four suspected Al Qaeda members in a vehicle in the eastern province of Shabwa. They declined to provide further details.

U.S. drone strikes are common in the country's lawless hinterlands, but in recent days the unmanned aircraft have been increasingly visible over the capital, causing growing unease among residents. The officials said the increasing drone presence is related to concerns about Al Qaeda militants.

Al Qaeda in the Arabian Peninsula captured large areas of Yemen in the aftermath of the country's 2011 uprising, which left the security forces in disarray.

In two large offensives, in 2012 and 2014, U.S.-backed Yemeni forces launched assaults on Al Qaeda strongholds, driving the extremists into the mountains. Al Qaeda's counterattacks, including suicide bombings, have killed scores of people, mainly soldiers and police.