The armed group Ansar Bayt al-Maqdis has claimed responsibility for a tourist bus bombing in Egypt's Sinai Peninsula that killed four people.
Monday's incident left three South Korean tourists and an Egyptian bus driver dead and marked a shift in tactics among Sinai's fighters, who are attacking "softer" tourist and economic targets.
The group said in a statement on Tuesday: "Ansar Bayt al-Maqdis has successfully sacrificed one of its heroes to detonate the bus headed toward the Zionists, and this comes as part of our economic war against this regime of traitors.
"With God's will we will be watching this treacherous gang of inflitrators and we will target their economic interests in all places in order to paralyse their hands from (hurting) Muslims."
Ansar Bayt al-Maqdis has claimed responsibility for several bombings, including an attempt to kill the interior minister in Cairo last year. The organisation also said it was behind a missile attack on a military helicopter last month that killed five soldiers.
Egypt's vital tourism industry has already been damaged by three years of political turmoil and street protests.