Slain Hamas chief to be buried in Qatar as militants ready response

Haniyeh, who lived in Doha, will be buried in Lusail, north of the Qatari capital. [AFP]

Mourners arrived at a Qatari mosque on Friday to farewell Hamas leader Ismail Haniyeh after his killing in Tehran, an attack blamed on Israel that deepened fears of wider war.

Haniyeh, the Palestinian armed group's political chief, played a key role in mediated talks aiming to end nearly 10 months of war between his Islamist movement and Israel in Gaza.

His killing triggered calls for revenge and raised questions about the continued viability of such negotiations.

Haniyeh, who lived in Doha along with other members of the Hamas political office, will be buried in Lusail, north of the Qatari capital, after funeral prayers at Imam Muhammad bin Abdul Wahhab mosque, the Gulf emirate's largest.

His killing is among several incidents since April that have sent regional tensions soaring during the Gaza war which has drawn in Iran-backed militant groups in Syria, Lebanon, Iraq and Yemen.

Turkey and Pakistan announced a day of mourning on Friday to honour Haniyeh, while Hamas called for a "day of furious rage".

Hours before the prayers, hundreds of mourners had already arrived at the Doha mosque.

Most donned scarves bearing the Palestinian flag or traditional keffiyeh patterns for the ceremony held under tight security.

Doha traffic police and Qatar's internal security forces monitored all approaches and police lined highway embankments adjoining the mosque grounds.