Israeli elder statesman Shimon Peres has suffered a heart attack and was undergoing surgery at a hospital near Tel Aviv, Israel's Channel 10 television said.
A Peres aide confirmed that the 92-year-old former prime minister and president had been taken by ambulance to Sheba hospital in Tel Hashomer with an irregular heartbeat.
"He is conscious and talking but still has chest pains," the aide, Ayelet Frisch, told Israel's Army Radio.
The hospital's spokesperson could not immediately be reached for comment.
Polish-born Peres is credited with setting up Israel's nuclear capabilities, and won the Nobel Peace Prize for his role in the 1993 interim peace deal with the Palestinians.
He has served twice as prime minister and was president from 2007-2014.