Five years since a coalition of Arab states led by Saudi Arabia launched a military intervention against the Houthi rebels in Yemen, the movement continues to advance in the north of the country.
In recent weeks, the group has taken control of the territory in Jawf province, including its main city of Hazm, which is located northeast of the capital, Sanaa, while also pushing parts of Marib province, rich in resources, Yemen's last international stronghold. Government recognized in the north.
Houthi's advances against forces loyal to President Abd-Rabbu Mansour Hadi and his regional allies have come despite the financial power of the Saudi-led coalition and the continued international and domestic isolation of the rebel movement.
Encouraged by his group's military progress in recent months, Houthi leader Abdelmalek al-Houthi has urged the coalition, led by Saudi Arabia and the United Arab Emirates, to stop the attacks.
Before the coalition began air strikes on March 26, 2015, the Houthis had forced President Hadi to flee to the southern city of Aden after temporarily holding him under house arrest.
They had also seized most of the populated highlands of northern and central Yemen. Houthi control of the country's air force meant that they were able to bombard pro-government forces in Aden, and almost took full control of the city. Hadi fled to Saudi Arabia the day before Riyadh launched its aerial intervention.
Within months, Saudi Arabia, the United Arab Emirates and their allies on the ground pushed the Houthis from southern Yemen toward their northern heart.
"The most important success of the war has been to prevent the Houthis from controlling all of Yemen, or most of them, especially the oil and gas rich areas," said Abdulnaser Almuwadea, a Yemeni political researcher.
"The Houthis have been unable to obtain international recognition, which would have been a possibility if the Houthis had taken control of Yemen and had not faced any local resistance."
But the intervention and the protracted conflict have sparked what the UN describes as the world's worst humanitarian crisis in the poorest country in the Middle East.
More than 100,000 people have died in the war, according to ACLED (location of armed conflict and event data), including 12,000 civilians. According to the World Food Program, 24 million Yemenis need humanitarian assistance, while 20 million are food insecure.
"The air strikes that hit civilian areas and infrastructure have led fewer Yemenis to support the war, and the Houthis have been able to really take advantage and grow their base," said Almuwadea.
"The weakness of the Yemeni government and the absence of its real presence on the ground in many areas … has strengthened the Houthis and made their control of the north more entrenched."
Houthi's control over Sanaa and the northern highlands seems fairly secure, but the group has few internal allies as it has fought most of the other major factions in Yemen, including the loyal Hadi, the southern separatists, the pro-Islah party militias and loyalists of the ancients. President Ali Abdullah Saleh.
Saleh helped the Houthis take control of Sanaa in 2014, but was killed in December 2017 by Houthi fighters, who suspected that he was preparing to ally with the Saudi-led coalition.
His death marked the end of a brief period of fighting between the Houthis and forces loyal to the former leader, and perhaps the last real chance for the Saudi-led coalition to defeat the Houthis in their northern fortress.
While Saleh's death sparked a certain merger of non-Houthi forces around the Hadi coalition government, the anti-Houthi alliance was weak and has since fractured.
When the coalition advanced into the Houthi-controlled port city of Hodeidah in the second half of 2018, it looked like it could result in a military victory for the alliance, but international fears that the fight would cause a humanitarian catastrophe allowed the Diplomatic pressure stopped the advance. .
Since then, anti-Houthi forces have turned to each other, as divisions between officially allied groups developed.
Secessionist Southern Transitional Council (STC), a group backed by the United Arab Emirates that has broad support throughout southern Yemen, forced government forces to abandon their temporary capital of Aden in August 2019.
This led to the worst fight between anti-Houthi forces since the beginning of the war, as the fighting spread across southern Yemen. It also led to increasingly apparent divisions between Saudi Arabia and the United Arab Emirates, which supported the government and the STC, respectively.
A deal negotiated by Saudi Arabia in November 2019 was supposed to bring the two sides back together, but has yet to be fully implemented.
"The anti-Houthi alliance on the ground has profound ideological differences that may not be easy to overcome," said Fatima Abo Alasrar, a nonresident academic at the Middle East Institute.
"The Hadi government will have to quickly incentivize other factions to unite their efforts under one banner, but this could be too ambitious to wait at this stage of the Yemen conflict."
The STC itself continues to insist that it will not back down to press for secession from the south.
"The STC is the political representative of the people of the south and will negotiate to end the crisis in Yemen in a way that guarantees a just solution to the problem of the south," STC member Nasr Alesayi told Al Jazeera.