Mubarak termed the killing "regrettable and cowardly" when he spoke to reporters after meeting with U.S. Middle East envoy William Burns.
Israeli helicopter gunships killed Yassin, the founder and spiritual leader of the violent Hamas (search) movement, in a missile attack as he left a mosque near his house in Gaza.
Asked about the killing's likely impact on the peace process, Mubarak replied: "What peace process?"
Shortly afterward, Egyptian state television broadcast that Mubarak had canceled the visit by Egyptian legislators and other dignitaries to Israel. The delegation had planned to go to Jerusalem to take part in Tuesday's ceremonies in the Israeli parliament of the 25th anniversary of the signing of the Camp David peace treaty between Egypt and Israel.