(Reuters) - Blocked road access to people hit by Afghanistan's earthquake has been the biggest challenge for response teams, and rescue efforts in the impacted mountainous regions are relying on helicopters, a United Nations official said on Tuesday.

"There's been lots of landslides and rock falls, and access has been very limited to everybody in the first 24 hours," Indrika Ratwatte, the United Nations' humanitarian coordinator in Afghanistan, said in a press briefing, speaking from Kabul.

"The biggest challenge is to reach these remote areas with the road access extremely damaged," he added.

(Reporting by Ludwig Burger, Editing by Rachel More)