The Houthi group does not observe the international law in dealing with prisoners, Guards of the Republic commander tweeted on Friday.
"One year has passed since the last phone call they allowed for the two captive heroes, Mohamed and Affash," Tariq Saleh added, hinting at his brother and son.
In December 2017, the Yemeni general engaged in fighting with the Houthis (once his allies) leaving his uncle, former President Ali Abdullah Saleh, killed in Sana'a.
"The Houthis have neither agreed to prisoner swap nor observed the international criteria in dealing with prisoners," Tariq said, dubbing the group as "wicked rival that has no religion or morals."
Aref al-Zokka, former secretary-general of Saleh (GPC) party, was among the 240 people killed in December 2017 clashes that left also 420 people injured.
The Houthis then arrested some 2,000 political and military leaders loyal to the late president and some of his family members.
