A powerful earthquake has hit both sides of the Iran-Pakistan border, killing at least 34 people in Pakistan and injuring 80.
All the casualties were so far in the town of Mashkeel in Pakistan's southwestern Balochistan Province.
Iran's official IRNA news agency said the authorities had declared a state of emergency in the border area, but so far there have been no confirmed deaths on the Iranian side.
Iranian state-run television initially reported 40 deaths but the governor of Iran's Sistan and Baluchistan Province was later quoted as saying there were "no fatalities."
The U.S. Geological Survey said the earthquake had a magnitude of 7.8. It was centered near the Iranian town of Saravan, about 50 kilometers from the border.
"People are scared," one resident told RFE/RL's Radio Farda within an hour or so of the quake. "They have left their homes because the tremors were very powerful. People are still staying outside their homes."
Tremors were felt througout the Persian Gulf region and South Asia, including in the Indian capital, Delhi, causing people to rush out into the streets.
Reuters quoted an unnamed Iranian official as saying it was "the biggest earthquake in Iran in 40 years" and warning that "we are expecting hundreds of dead."
The Iranian Red Crescent said rescue teams had been dispatched. Red Crescent officials said all communications to the region had been cut.
Hatam Narui, the governor of Sistan and Baluchistan Province, where the earthquake was centered, told state television the tremors lasted between 15 and 20 seconds.
Iran sits on a region with a history of seismic volatility.
A week ago, a 6.3-magnitude earthquake hit southwest Iran
, killing dozens of people and injuring at least 850 others.
Provincial Governor Fereydoun Hassanvand told state television after that April 9 event that the nearby Bushehr nuclear plant had not been affected.
Based on reporting by RFE/RL and RFE/RL's Radio Farda; with additional reporting by AFP and Reuters