World leaders are beginning to understand the threat of extremist Islam, Israeli Prime Minister Benjamin Netanyahu said Tuesday at the funeral of four Jews killed by an Islamist gunman in Paris.

"I think that most (world leaders) understand -- or are at least starting to understand -- that this terror committed by extremist Islam represents a clear and present threat to peace in the world in which we live," he said.

"Islamist terror ... is not just the enemy of the Jewish people but of all humanity. It is time all people of all cultures united to eject these elements from among us."

The bodies of the four Jews were flown to Israel for burial following the assault Friday on a kosher supermarket in eastern Paris.

They were among 17 people gunned down during three days of bloodshed that began with an attack on the satirical weekly Charlie Hebdo, sending shock waves through the Jewish community.