A major earthquake, described as the strongest to hit Iran in more than half a century, flattened homes and offices on Tuesday near Iran's border with Pakistan, killing at least 62 people in the two countries and swaying buildings as far away as New Delhi and Dubai.

Iran's state-run Press TV called it a "massive quake," saying at least 40 people were killed in the sparsely populated region, but gave no other immediate details on casualties or the extent of damage.

Pakistan's TV channel Express, meanwhile, said at least 22 people were killed on its side of the border and at least 100 others were injured. Up to 1,000 mud homes were damaged, it added.

Iran's Red Crescent said it was facing a "complicated emergency situation" in the area with villages scattered over desolate hills and valleys.

Power and communications systems were down in most of the country's southeastern provinces of Sistan and Baluchistan, Iranian state television reported.

Iran's semiofficial ISNA news agency and others described the quake - which was centered near Saravan, about 48 km from the Pakistani border - as the strongest in more than 50 years. The US Geological Survey put its preliminary magnitude at 7.8 and its depth at 15.2 km.

The quake was felt over a vast area from New Delhi to Gulf cities that have some of the world's tallest skyscrapers, including the record 828-meter Burj Khalifa in Dubai. Officials ordered temporary evacuations from some high-rises as a precaution.

In India's capital, New Delhi, the earthquake sent people running into the streets, witnesses said.

"I was working and my work station was shaking," said Viidhu Sekhri, 35, an underwriter at a New Delhi insurance company. "Then it was a bit shaky so we just rushed outside."

A resident in the quake zone, Manouchehr Karimi, told The Associated Press by phone that "the quake period was long" and occurred "when many people were at home to take a midday nap".

Pakistani news channels showed buildings shaking in the southern city of Karachi, where panicked people came out from offices and homes.

It was also the second deadly quake to hit Iran in less than a week after a magnitude-6.1 temblor struck near Bushehr, on Iran's Persian Gulf coast, killing at least 37 people and raising calls for greater international safety inspectors at the country's lone nuclear reactor, which is located nearby.

In a message posted on Twitter, British Foreign Secretary William Hague sent condolences to families of those lost in the Iran earthquake.

Iran sits on major geological fault lines and has suffered several devastating earthquakes, including a 6.6-magnitude quake in 2003 that flattened the city of Bam, in Iran's far southeast, killing more than 25,000 people.

Reuters-AP-AFP-Xinhua