Lack of funds and unrest are hampering efforts to evacuate thousands of Ethiopian migrants stranded in Yemen, the International Organisation for Migration said on Tuesday.

"Events in Yemen in the past few days have complicated even more the IOM's efforts to evacuate around 3,000 Ethiopian migrants who are stranded in the Haradh district at the border with Saudi Arabia," IOM spokesman Jean-Philippe Chauzy told reporters.

"But the main stumbling block is that we have run out of money," he said, adding the IOM would need $2.5 million (1.8 million euros) to resume evacuation operations.

On Tuesday, gunfire and shelling rocked Yemen's capital Sanaa for the third straight day as the toll from the worst outbreak of violence in Yemen's capital in months spiralled to 60 dead with hundreds wounded.

"We are caught between a rock and a hard place," Chauzy said, explaining that many of the migrants had crossed into Yemen with the idea of going on to Saudi Arabia to find work in the informal sector.

"We are providing assistance on a daily basis to the most vulnerable... we are daily reminded of their needs to be evacuated. They come to our office and say 'help us go home'," he said.

Chauzy added that in the past 10 months the IOM had evacuated around 5,000 migrants, mostly Ethiopians, who were stuck in Haradh, but that lack of funds were preventing the operations from continuing.