London Mayor Sadiq Khan called on Friday for a ceasefire in the Israel-Hamas war, going a step beyond his Labour Party’s appeals for a humanitarian pause in fighting to allow aid into the Israeli-besieged Gaza Strip.

The apparent difference in stance between Khan and Labour leader Keir Starmer highlights disagreement and growing unrest within Britain’s main opposition party over its position on the conflict.

Khan, a senior voice within Labour and one of the UK’s most prominent Muslim politicians, said he backed Israel’s right to defend itself but that a military escalation could worsen a humanitarian crisis in Gaza.

“I join the international community in calling for a ceasefire. It would stop the killing and would allow vital aid supplies to reach those who need it in Gaza,” Khan said in a video posted on X, formerly Twitter.

A Labour spokesperson did not respond to a request for comment on Khan’s statement.

Labour, which polls indicate has a strong chance of forming Britain’s next government in an election expected in 2024, called this week for a pause in fighting, echoing similar appeals by the U.S., European Union and Britain’s Conservative government.

Such pauses are seen as a measure short of a full ceasefire, but critics say it does not go far enough.