At least 25 people were killed in a suicide attack on Friday on a Shi'ite Muslim mosque in Kuwait City, the governor of Kuwait City Thabet al-Muhanna said.
Speaking by telephone from Kuwait, Muhanna told Reuters that several more people were in critical condition.
A witness said the bombing happened when the mosque was packed with some 2,000 worshippers during Friday prayers
Militant group Islamic State claimed responsibility for the suicide attack, according a statement posted on social media.
The statement identified the bomber as Abu Suleiman al-Muwahed and said the target was a "temple of the rejectionists" - a term used by the Islamist militant group to refer to Shi'ite Muslims - and said dozens were killed or wounded.