Egyptian military spokesman Ahmed Ali announced that the commander of Al-Tawhid Wal-Jihad, Ahmed Hamdan Harb Malki alias Abu Mariam, was killed during operations aimed at securing the peninsula, which borders Hamas-ruled Gaza Strip.
"The military was able to kill three Islamist figures, including Abu Mariam, in an exchange of fire between the militants and the army," Ali said in a statement.
Egyptian forces have stepped up crackdown on Islamists in Sinai whose attacks on the army and police rose dramatically following the ouster of Islamist president Mohamed Morsi last July, Al-Ahram Online reported.
According to Al-Ahram Arabic news website, 175 members of the armed forces have been killed in terrorist attacks, with 185 militants killed during security operations.
Gas pipelines in Sinai have come under attack on several occasions over the past three years, since the downfall of longtime president Hosni Mubarak in 2011.