A powerful suicide bombing ripped through the Yemeni capital on Thursday, killing at least 47 people and plunging the violence-plagued country into further turmoil after weeks of political deadlock.
Dozens more were wounded in the attack in Sanaa's Al-Tahrir square, which targeted a gathering for supporters of Shiite insurgents who overran the capital last month.
A separate suicide attack killed 20 soldiers in southeastern Yemen in a car bombing suspected of having been carried out by Al-Qaeda, a military source told AFP.
Yemen has been wracked by political turmoil and sporadic violence since the 2011 uprising that toppled strongman Ali Abdullah Saleh, with rebels and militants battling to exploit a power vacuum.
The bombing in Sanaa came a day after Yemen's new prime minister designate, named as part of a UN-brokered peace deal, refused the post amid fierce rebel opposition.
The health ministry said 47 people were killed and 75 others wounded.
Witnesses said a suicide bomber detonated an explosive belt at a checkpoint at the entrance to the protest gathering, adding steel balls were seen strewn at the scene of the blast.
"He came to the security (checkpoint) and blew himself up while being checked," witness Abdulsalam Amer told AFP, describing "bodies lying on the ground".
The lifeless bodies of four children could be seen among the victims, while footage aired by rebel-linked Al-Masirah television showed corpses lying in pools of blood in the street.
Supporters of the rebels, known as Huthis, gathered after the blast -- the largest in Sanaa since May 2012 -- demanding the fall of beleaguered President Abdrabuh Mansur Hadi.
In a meeting with foreign ambassadors, Hadi condemned the "coward terrorist bombing".
The United States strongly condemned what it called a "despicable attack against civilians".
"The Yemeni people have lived with senseless violence for far too long and the recent increase in hostilities against innocent civilians only undermines the progress Yemen has made in achieving meaningful reform since 2011," State Department spokeswoman Jen Psaki said.
Iran also expressed condolences over "this blind and inhuman act of terrorism".
The Huthis, who are also referred to as Ansarullah, swept into the capital on September 21 after fierce battles with forces allied to the government in Sanaa that left more than 270 dead.
A UN-brokered peace accord, which called for a rebel withdrawal from Sanaa and the naming of a neutral premier, was struck the same day.
But the Huthis have dug their heels in, refusing to support Hadi's choice for prime minister and demanding a greater role in decision making as well as political and economic reform.
Signup to our newsletter and follow us on Facebook and Twitter!
- 'Al-Qaeda' bombing -
In addition to the Huthis swooping south from their Saada stronghold in the north, the authorities have also had to deal with southern secessionist aspirations and a bloody campaign by the country's Al-Qaeda franchise.
The 20 Yemeni soldiers were killed on Thursday when a suspected Al-Qaeda operative detonated his explosives-laden car at an army post on the western outskirts of the southern city of Mukalla, a military official said.
A tank and two army vehicles were destroyed in the blast, the official added.
On Wednesday, suspected Al-Qaeda militants launched a wave of dawn attacks on police and the army in another central town, killing 10 policemen.
Al-Qaeda in the Arabian Peninsula is considered by the US to be the global jihadist network's most dangerous branch and its attacks against security installations across the country have challenged Yemen's longtime role as an effective ally in Washington's fight against extremists.
Its proximity to oil-rich Saudi Arabia and key shipping routes in the Gulf of Aden have also raised fears that it could become a failed state similar to Somalia.
- 'Will of the nation' -
April Longley, a Yemen expert at the International Crisis Group, said there was a significant danger of further violence.
"The risk is high and continues to grow," she said. "Al-Qaeda has openly called for more attacks and they should be expected."
Yemen remains in political deadlock after Hadi infuriated the rebels in Sanaa earlier this week by naming his chief of staff, Ahmed Awad bin Mubarak, as prime minister as part of the UN's reconciliation accord.
Bin Mubarak took his decision "in a bid to preserve the national unity and protect the country from divisions," Saba said citing a letter sent by the PM-designate to Hadi.
In a statement on Wednesday the rebels said bin Mubarak's appointment had been "against the will of the nation" and "at the behest of outside forces," an apparent reference to US and Saudi influence.
Since storming into Sanaa, the rebels have been tightening their grip on the city while also looking to expand their control eastwards to oilfields and to the strategic southwestern strait of Bab el-Mandab.