Washington, Feb 14 (IANS): A US-born NASA scientist of Indian-origin was detained by US Customs and Border Patrol (CBP) officials and was not permitted to enter the country unless he unlocked his PIN-protected work phone.

Sidd Bikkannavar, who works in NASA's Jet Propulsion Laboratory (JPL), was detained on January 30, upon returning to the US from Santiago, Chile, a US media network, the Verge, reported.

Bikkannavar said he was pressured to give the CBP agents his phone and access PIN. Since the phone was issued by NASA, it may have contained sensitive material that wasn't supposed to be shared. Bikkannavar's phone was returned to him after it was searched by CBP, but he doesn't know exactly what information officials might have taken from the device.

Bikkannavar is a natural-born US citizen enrolled in CBP's Global Entry programme, which allowed participants who have undergone a background check to speed up their entry into the US.

He had not visited any of the countries mentioned in Donald Trump's Muslim travel ban, but Bikkannavar told the Verge that agents may have become suspicious about his family name, which is southern Indian.

The JPL scientist returned to the US four days after the signing of a sweeping and controversial executive order on travel into the country. The travel ban caused chaos at airports across the US, as people with visas and green cards found themselves detained, or facing deportation.

Within days of its signing, the travel order was stayed, but not before more than 60,000 visas were revoked, according to the US State Department.

"Sorry for my absence. On my way back home to the US last weekend, I was detained by Homeland Security and held with others who were stranded under the Muslim ban," he wrote on Facebook.

"CBP officers seized my phone and wouldn't release me until I gave them my access PIN for them to copy the data. I initially refused since it's a JPL-issued phone and I must protect access."

He added: "Just to be clear -- I'm a US-born citizen and NASA engineer, traveliing with a valid US-visa."

Bikkannavar said he was eventually released. His employers gave him a new phone.

According to the Verge, Bikkannavar was yet to receive an explanation for why he was stopped at Houston's George Bush Intercontinental Airport.

He had travelled to South America for personal reasons, pursuing his hobby of racing solar-powered cars. He had recently joined a Chilean team.

"It was not that they were concerned with me bringing something dangerous in, because they didn't even touch the bags," he said.

"They had no way of knowing I could have had something in there. You can say, 'Okay well maybe it's about making sure I'm not a dangerous person', but they have all the information to verify that."

Earlier this week, Homeland Security Secretary John Kelly said in a statement that people visiting the US may be asked to give up passwords to their social media accounts.

"We want to get on their social media, with passwords: What do you do, what do you say," Kelly told the House Homeland Security Committee. "If they don't want to cooperate, then you don't come in."