Former Yemeni president Ali Abdullah Saleh was shot dead on Monday in a roadside attack after apparently switching sides in the country's civil war.
Saleh and his supporters formed an alliance with the country's Houthi rebels in 2014 against the internationally recognised government of president Abdrabu Mansur Hadi, Saleh's successor. But this alliance had broken down in recent days as fighting erupted on the streets of the Yemeni capital between the two sides.
The Houthis accused Saleh of a coup on Saturday after he said he was open to talks with the Saudi-led military coalition backing Mr Hadi's government. Two days later he was dead, with rebel sources saying Houthi fighters had stopped Saleh's armoured vehicle with an RPG rocket outside Sanaa before shooting him.
Fahed Al Sharafi, a leading member of the GPC, said Saleh had been betrayed by "some of his consultants who were in fact traitors and conspires".
"We kept advising him constantly not to ally with the rebels but unfortunately he didn't pay attention to us and followed his obstinacy but what done is done no use of crying over the spilt milk," Mr Al Sharafi told Saudi Arabia's Al Arabiya news channel.
Earlier in the day, Sanaa residents had told The National that the Houthis were besieging Saleh's palace, as well as residences belonging to his relatives and prominent supporters. The rebels later said they had blown up Saleh's home.
The violence comes amid a civil war in which renegade soldiers loyal to Saleh and Houthi militants had together been fighting pro-government forces backed by the Saudi-led coalition.
Fighting first broke out after the Houthis seized Sanaa in September 2014 and later advanced south, forcing the internationally recognised government of president Abdrabu Mansur Hadi to relocate to the southern city of Aden.
Cracks began to emerge in the Houthi-Saleh alliance earlier this year when both sides accused each other of jeapordising the partnership. The two camps eventually agreed to restore calm but remaining tensions came to a head last week when fighting broke out between Saleh loyalists and the Shiite rebels.
On Saturday, fighters loyal to Saleh appeared to have gained the upper hand, with some political analysts predicting that the city would fall completely to them within hours. The following day the Houthis began to dramatically reverse the Saleh loyalists' gains, however.
As news broke of Saleh's death on Monday, the UN humanitarian coordinator for Yemen, Jamie McGoldrick, called for a pause in the fighting in Sanaa, noting that dozens of people had reportedly been killed and hundreds injured, including civilians.
Aid organisations were receiving desperate calls for help from families trapped in neighbourhoods engulfed by fighting, he said.
Meanwhile, Mr Hadi, Yemen's president, ordered his forces to retake the capital from the Houthis, an official from his office said.
"The president has ordered vice president Ali Mohsen Al Ahmar, who is in Marib [east of Sanaa], to activate military units and advance toward the capital."
Mr Al Sharafi, the GPC member, said his party would now co-ordinate with the "legitimate authority represented by the legitimate president Abdrabu Mansur Hadi" and called upon military commanders from the renegade elite Republican Guard, which is loyal to Saleh, to rejoin the Yemeni army in order to liberate the capital.
Mansoor Saleh, a Yemeni political analyst and member of the secessionist Southern Transitional Council's media department, said this was the only choice left open to military commanders aligned with the GPC.
"Many of the GPC commanders were killed with Saleh and the rebels will not give a chance for Saleh loyalists to capture their breath — they will keep filtering Sanaa of them."
The analyst noted that Saleh, with whom all of the party's power had been concentrated, had not assigned a successor.
"I don't think that either the GPC leaders or its members" will be able to recover from this, he added.
Houthi leader Abdul Malik Al Houthi, meanwhile, hailed the death of his former ally, congratulating Yemenis "on this historic, exceptional and great day in which the conspiracy of betrayal and treason failed".
He said his movement would not pursue a vendetta against Saleh's party, however.
"The problem is not with the General People's Congress as a party or with its members."
Saleh ruled Yemen for more than three decades until he was forced to resign following an Arab Spring uprising in 2011. After a short exile in Saudi Arabia he returned to the country, and continued to wield power from behind the scenes.
In 2014, his forces allied with the Houthis despite the fact that as president he had gone to war with them on more than one occasion.
Earlier on Monday, Abdullah Saleh, a resident living in Sanaa's southern Al Sabaeen district, said the Houthis had stormed the homes of numerous Saleh loyalists in the nearby neighbourhoods of Hadah and Beet Bous and besieged the homes of sheikhs close to the former president.
Local broadcast journalist Ra'afat Al Yarrisi said the Houthis had arrested several commanders of the Republican Guard, which is led by Saleh's nephew Col Tariq Mohamed Abdullah Saleh.
He said they had targeted several media outlets affiliated with the former president, including the television channel for which he works, Yemen Today, which was owned by Saleh.
"They stormed the TV channel and Al Yemen Al Youm newspaper headquarters and arrested some of my colleagues and started storming our residences," Al Yarrisi said.
Before Sunday night, he said Republican Guard soldiers had been in control of most of the capital's streets and the rebel-run government headquarters, but that the Houthis had made dramatic gains in recent hours.
"Suddenly we were told that the Houthis are besieging Hadah which is considered a stronghold for the General People's Congress party and Saleh's loyalists," said Al Yarrisi.
The rebels "started shelling the channel's headquarters. In that critical moment I and my colleagues headed to evacuate our families from Hadah. I decided to flee to Al Dhalaa province in the south of the country".
* Additional reporting from Reuters