Sen. Bill Nelson says the United States should waste no time hitting back at the Islamic State of Iraq and Syria, the terrorist group that claimed Tuesday to have executed American journalist Steven Sotloff.

“Let there be no doubt, we must go after ISIS right away because the U.S. is the only one that can put together a coalition to stop this group that’s intent on barbaric cruelty,” said the Florida Democrat in a prepared statement.

Nelson, a member of the Senate Armed Services Committee, added, “Our hearts go out to the family and friends of Steven Sotloff,” a freelance journalist who went missing in Syria in August 2013.

ISIS also executed U.S. freelance journalist James Foley two weeks ago.