"We are required to intensify efforts with the world to combat terrorism being waged by terrorist organisations," Sheikh Sabah al-Ahmad Al-Sabah told attendees at a conference of the Organisation of Islamic Cooperation (OIC).
"We need to take a serious stand against sectarian tensions plaguing and dividing our nations... It is the most serious (threat) against the very existence of Muslim countries," the Kuwaiti emir said.
Iran, Turkey and Saudi Arabia are among countries attending the conference, which is expected to see the 57-member OIC approve an "effective strategy to combat terrorism, violent extremism and Islamophobia," the organisation said.
Signup to our newsletter and follow us on Facebook and Twitter!
The strategy, expected to be approved later Wednesday, will focus on Islamic world responses to the root causes of "terrorism", including poverty, underdevelopment, unresolved conflicts and sectarianism, the OIC said in a statement.
Sunni powerhouse Saudi Arabia was itself the scene of a suicide bombing by Sunni extremists against a Shiite mosque that killed 21 people during Friday prayers last week.
Sheikh Sabah defended the Saudi-led airstrikes against Yemen's Shiite Huthi rebels and their allies after they "threatened our security and stability and captured power by force".
He also urged Iran to cooperate with the international community to resolve the dispute over its nuclear programme and to respond to efforts by countries in the region to establish closer ties.
In a letter published in Kuwaiti newspapers Wednesday, Iranian Foreign Minister Mohammad Javad Zarif, who is attending the meeting, said his country was prepared to engage in dialogue in order to resolve the region's several conflicts.