Former Israeli President Shimon Peres is in hospital after suffering chest pains, 10 days after he had a small heart attack.
Mr Peres, 92, underwent minor surgery last week for a constricted artery.
A spokeswoman said on Sunday he was readmitted to a Tel Aviv hospital “for observation and testing”.
He was not due to undergo any invasive procedures, Haaretz reported. Mr Peres twice served as Israel’s prime minister and was president from 2007 to 2014.
On Sunday, he was found by doctors to have an irregular heartbeat, his spokeswoman said.
Mr Peres won the Nobel Peace Prize in 1994 for his role negotiating the Oslo peace accords with the Palestinians a year earlier, a prize he shared with Prime Minister Yitzhak Rabin, who was later assassinated, and Palestinian leader Yasser Arafat.
He was defeated in the 1996 election by the head of the opposition Likud, Benjamin Netanyahu.
Mr Peres has held almost every major political office since Israel was founded in 1948, and was the architect of Israel’s secret nuclear programme in 1959.
Despite his age, Mr Peres has maintained an active public schedule, mostly through his non-governmental Peres Centre for Peace, which promotes closer ties between Israel and the Palestinians.