CASABLANCA (Updated) — A powerful earthquake that struck Morocco Friday night has killed at least 632 people and injured 329 others, according to an updated interior ministry toll.

Of those injured, 51 were in a critical condition, the ministry said, after the 6.8-magnitude quake that struck 72 kilometers southwest of tourist hotspot Marrakesh.

"We felt a very violent tremor, and I realized it was an earthquake," Abdelhak El Amrani, a 33-year-old in Marrakesh, told AFP by telephone.

"I could see buildings moving. We don't necessarily have the reflexes for this type of situation. Then I went outside and there were a lot of people there. People were all in shock and panic. The children were crying and the parents were distraught."

"The power went out for 10 minutes, and so did the (telephone) network, but then it came back on. Everyone decided to stay outside," he added.

Fayssal Badour, another Marrakesh resident, told AFP he was driving when the earthquake hit.

"I stopped and realized what a disaster it was. It was very serious, as if a river had burst its banks. The screaming and crying was unbearable," he said.

Hospitals in Marrakesh reportedly saw a "massive influx" of injured people.

In the town of Al-Haouz, near the epicenter of the quake, a family was trapped in the rubble after their house collapsed, local media reported.

Significant damage likely

The earthquake was also felt in the coastal cities of Rabat, Casablanca and Essaouira.

"There's not too much damage, more panic. We heard screams at the time of the tremor," a resident of Essaouira, 200 kilometers west of Marrakesh, told AFP.

"People are in the squares, in the cafes, preferring to sleep outside. Pieces of facades have fallen."

US Geological Survey's PAGER system, which provides preliminary assessments on the impact of earthquakes, issued an orange alert for economic losses, estimating significant damage is likely.

Past events with this alert level have required a regional or national-level response, according to the US government agency.

USGS said that "the population in this region lives in structures that are highly vulnerable to earthquake shaking".

Internet connectivity was disrupted in Marrakesh due to power cuts, according to global internet monitor NetBlocks.

Moroccan media reported it was the most powerful earthquake to hit the country to date.

The earthquake was also felt in neighboring Algeria, where the Algerian Civil Defence said it had not caused any damage or casualties.

In 2004, at least 628 people were killed and 926 injured when a quake hit Al Hoceima in northeastern Morocco.

The 1980, the 7.3-magnitude El Asnam earthquake in neighboring Algeria was one of the largest and most destructive earthquakes in recent history. It killed 2,500 people and left at least 300,000 homeless.

© Agence France-Presse