WASHINGTON—Sen. Mark Kirk (R-Ill.), a leader on pro-Israel and Iran sanctions issues, suffered a stroke.

A statement from Kirk’s office said he checked himself into a hospital on Saturday, and that doctors discovered he had suffered a stroke.

“Early this morning the Senator underwent surgery to relieve swelling around his brain stemming from the stroke,” the statement, issued Monday, said. “The surgery was successful. Due to his young age, good health and the nature of the stroke, doctors are very confident in the Senator’s recovery over the weeks ahead.”

Kirk, 52, who with Sen. Robert Menendez (D-N.J.), helped craft the latest Iran sanctions, has strong Jewish and pro-Israel backing.

He is seen as a relative Republican moderate on social issues.

He was elected to the Senate last year to the seat Barack Obama left open when he won the presidency in 2008. Previously, he represented Illinois’ 10th district, the heavily Jewish district comprising parts of Chicago and its northern suburbs.