Turkey's leader is seeking to spearhead Islamic reaction to the US declaration on Jerusalem, but it is uncertain if he can coordinate a meaningful response among often disunited Muslim nations.
President Recep Tayyip Erdogan, who regards himself as a champion of the Palestinian cause, had fulminated against President Donald Trump's recognition of Jerusalem as Israel's capital even before it was officially announced this week.
Erdogan described the status of the city, whose eastern sector Palestinians see as the capital of their future state, as a "red line" for Muslims.
The Turkish president used his position as the current chairman of the Organisation of Islamic Cooperation (OIC) to call a summit of the pan-Islamic group.
The Istanbul summit of the OIC -- an organisation founded in 1969 after an arson attack on the Al-Aqsa mosque in Jerusalem -- will offer Erdogan the chance to showcase his status as a global Muslim leader.
But it remains unclear if he will be able to come close to shifting the 57 members -- including arch foes like Shiite Iran and Sunni Saudi Arabia --- into anything resembling a coordinated position.
Turkey in 2016 agreed to resume full diplomatic relations with Israel after the crisis triggered by the deadly storming by Israel of a Turkish ship seeking to break the Gaza blockade in 2010.
Cooperation has resumed, most significantly in energy. But Erdogan has rarely mustered much public enthusiasm for ties with Israel and retains warm relations with Hamas, the Palestinian Islamist group that controls Gaza.
The Turkish leader has left diplomatic niceties aside in warning his US counterpart of the dangers of the move, using the backyard-style rhetoric he usually keeps for bitter enemies.
Trump's arrival as US leader was welcomed by Ankara but relations have hit new trouble due to rows over the Syria conflict, an explosive legal case in New York and even a mutual visa suspension, reports AFP.