"I don't think that requiring back doors to encryption is either going to be an effective thing to increase security or is really the right thing to do. We are pretty sympathetic to Tim and Apple," he said at a the world's biggest mobile congress in Barcelona.

"At the same time we feel we have a really big responsibility running this big networking community to help prevent terrorism and different types of attacks”, Zuckerberg said.

"If we have opportunities to basically work with the government to make sure there are not terrorist attacks, obviously we are going to take those opportunities", he added.

The controversy emerged earlier this month when Apple refused to help the FBI break into an iPhone belonging to the late Syed Farook, who along with his wife went on a deadly shooting rampage in California's San Bernardino in December.

Apple claims that cooperating with the probe would undermine privacy and security for its devices, while the US government counters it is a one-time request that will aid an important investigation.

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