Istanbul's Hagia Sophia - a Byzantine-era cathedral that now serves as a museum - could be reconverted into a mosque, Recep Tayyip Erdogan, the Turkish president, has said.

Mr Erdogan made the comments during a television interview late on Sunday ahead of Turkey's March 31 local elections.

The former Byzantine cathedral had previously been converted into a mosque after the Ottoman conquest of the city, then-known as Constantinople, in 1453.

Turkey's secular founder, Mustafa Kemal Atatürk, turned the structure into a museum in 1935 that attracts millions of tourists each year.

There have however, been increasing calls for the government to convert the symbolic structure back into a mosque, especially following reports that the gunman who killed Muslim worshippers in New Zealand left a manifesto saying the Hagia Sophia would be "free of minarets."