Yemen's Houthi rebels are blocking relief supplies to the embattled city of Taiz, advocacy group Human Rights Watch (HRW) said Sunday.
Yemen's third-biggest city has in recent months been at the centre of fighting between the Iran-allied Houthis and forces loyal to internationally recognized President Abd Rabu Mansour Hadi.
The rebels are besieging Taiz, where pro-Hadi forces control the city centre.
"The Houthis are denying necessities to residents of Taiz because they happen to be living in areas that opposition forces control," Joe Stork, HRW's deputy Middle East director, said in a statement.
Taiz had a pre-war population of about 600,000, but heavy ground fighting in the armed conflict that began in March has caused two-thirds of the population to flee, with between 175,000 to 200,000 civilians remaining, according to the United Nations.
Since September, rebels manning checkpoints at the city’s two main entry points have confiscated water, food, and cooking gas that Taiz residents tried to bring into the areas controlled by the anti-Houthi forces, HRW said.
Taiz is located between the rebel-held capital Sana'a and the port city of Aden, which is controlled by pro-Hadi forces.
In July, the pro-government forces recaptured Aden from the Houthis. However, the southern city has since seen an uptick in attacks, several of them claimed by the Islamic State terrorist militia.
Unknown gunmen Sunday killed a senior pro-Hadi militiaman in Aden, independent Yemeni news website Change reported.
Samhan al-Rawi, a commander in the pro-government Popular Resistance militia and a prominent Muslim cleric, was abducted late Saturday and later shot dead, according to the report.
His body was found abandoned in an Aden suburb.
No one has claimed responsibility.
Yemen's conflict has intensified since March when the Houthis first advanced on Aden, prompting Saudi Arabia and allies to launch airstrikes against the Shiite group in support of Hadi.
Saudi Arabia fears that the rebels will give its regional rival, Shiite Iran, a strategic foothold on the Arabian Peninsula.