In a telephone conversation with UN Special Envoy for Iraq Yan Kubish, Ayatollah Seyed Mohammad Saeed Hakim voiced concerns over the declining role of the UN in supporting the Shias in the two besieged towns, Ittijah website reported.
He noted that residents of Kafariya and Al-Foua are living in tragic humanitarian conditions.
Ayatollah Hakim went on to say that the UN should prevent the massacre of the followers of Ahl-ul-Bayt (AS) by terrorist groups in the region.
The two towns have been under siege by the al-Nusra Takfiri terrorist group for months.
Syria has been gripped by civil war since March 2011 with Takfiri terrorists like al-Nusra and ISIL currently controlling parts of it, mostly in the east.
The US and its regional allies have been supporting the militants operating inside Syria for more than four years.