(CBS NEWS) -- A massive earthquake rocked Iran and nearby nations Tuesday morning. The U.S. Geological Survey said the magnitude was estimated at 7.8 and the depth at 51 miles.
The quake was centered near the border with Pakistan, in a sparsely populated region of southeast Iran.
Reports on Iran's Press TV said at least 40 people had been killed, but no official figures were given and the reports could not be immediately confirmed. Another Iranian news agency, the semi-official ISNA, quoted an official from the national emergency response agency as saying there had been no deaths in Iran due to the quake. It wasn't immediately possible to reconcile the varying reports coming from Iranian media.
A senior Pakistani official did confirm to CBS News' Farhan Bokhari, however, that five people were killed in that country as a result of the quake.
"The number of casualties could rise as reports come in from different parts of the region," added the official. Reuters reported that five people -- three women and two children -- were killed when their house collapsed in the Baluchistan region, which spans the Iran-Pakistan border.
Iran's Red Crescent said it was facing a "complicated emergency situation" in the area with villages scattered over desolate hills and valleys. Iran's semiofficial ISNA news agency and others described the quake as the strongest to hit the region in more than 50 years.
Buildings swayed in New Delhi, India, and CBS Radio News correspondent Toula Vlahou in Dubai, across the Persian Gulf, said the temblor was felt there, as well.
Across the Gulf, high-rise buildings swayed and officials ordered evacuations. Dubai has the world's tallest tower, the 2,717 -foot Burj Khalifa.
A businessman in Gwadar, a coastal Pakistani city about 200 miles from the epicenter, told Bokhari there was no significant damage in the area, but panicked people streamed out of their homes after the quake struck.
Tuesday's quake came less than a week after a 6.1 magnitude quake about 60 miles southeast of Bushehr, the site of Iran's main nuclear reactor, killed 37 people.
Iran is prone to quakes, and the nation's southern coast runs along the boundary of a tectonic plate. The southeastern corner of the country, near the epicenter of Tuesday's temblor, sits near the point where three separate plates meet.