O’Brien and his entourage were scheduled to visit Taiz, which has been besieged by Houthi militias and forces belonging to the ousted former president Ali Abdullah Saleh for almost two years.

Reports suggest Houthi militias have blocked UN humanitarian chief Stephen O’Brien’s motorcade access to besieged areas of Taiz.

O’Brien and his entourage were scheduled to visit Taiz, which has been besieged by Houthi militias and forces belonging to the ousted former president Ali Abdullah Saleh for almost two years.

When asked the reason why militias were blocked from entering Taiz, they were told that their safety was their main concern, sources told Al Arabiya English.

But sources said the militias has advanced knowledge of the pre-scheduled visit, and sources say the militias “staged an attack by firing and shelling the city since the early morning hours” to provoke the legitimate army and popular resistance forces to respond.

“The international community needs to step up its funding and the parties to the conflict need to continue providing humanitarian access,” O’Brien told journalists at the government’s base in Aden late on Monday.

“This also means access to the ports so that the needed imports can enter Yemen,” he said.