For the first time since beginning the project in late 2017, the International Crisis Group has listed "Critical" flashpoints in two separate Middle Eastern countries.
Despite reports that the Saudi-led coalition had seized a crucial port city, a top Iranian official said the Houthis were "witnessing their advances every day."
"The U.S. must stop backing this war and support the UN's effort to get a cease-fire."
A New York Times report claims U.S. Green Berets are covertly destroying Houthi rebel missile sites in Yemen on behalf of Saudi Arabia.
A Saudi royal decree has forced the kingdom's chief of the joint staff and air force commander out of their positions.
At least 10,000 civilians have been killed in the Yemen conflict.
Revolutionary Committee head Mohammad Ali al-Houthi welcomed Saudi princes and "any employee or person who feels targeted by the regime."
Fearless ISIS recruits in Yemen may have completed jihadi training, but not before being subject to an excruciating hazing routine.
Despite an aerial bombing campaign by Saudi Arabia, Shiite Muslim Houthi rebels have kept control of Sanaa and other parts of Yemen.
The International Committee of the Red Cross says the world has three to four months left to save millions of people in Yemen from starvation.
William Owens was killed in a ground attack on an al-Qaeda base in Yemen.
The rebels blamed the Saudi-led coalition for the airstrikes.
An estimated 63,000 children died last year of preventable causes often linked to malnutrition.
Previous ceasefires significantly slowed fighting, though have not yet ended the conflict.
Nineteen people were killed when a Saudi-led coalition airstrike hit an MSF facility in northern Yemen.
The claim has not been independently confirmed and civilian casualties are unknown.
Al-Qaeda in the Arabian Peninsula has taken advantage of conflict in the region.
The attack came days after the assassination of a prominent judge on the same street.
Humanitarian agencies said that the use of British weapons in the Yemen campaign is illegal.