Turkish President Recep Tayyip Erdogan said on Wednesday it was time to rename Istanbul's landmark Hagia Sophia as a mosque, saying that it had been a "very big mistake" to convert it into a museum.

"Hagia Sophia will not be called a museum. It will be taken out of that status. We will call Hagia Sophia a mosque," Erdogan told A Haber television during an interview.

"Those who come to Hagia Sophia will visit Hagia Sophia mosque," he said.

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The former church and mosque, now a museum, often sparks tensions between Christians and Muslims over Islamic activities held there, including the reading of verses from the Holy Quran or collective prayers.

Its secular status allows believers of all faiths to meditate, reflect or simply enjoy the astonishing architecture of a building dating back to the sixth century.

Erdogan is campaigning for votes for his Justice and Development Party (AKP) ahead of municipal elections on March 31.

The Turkish leader said the plan would be discussed after the elections. "We think the time has come to take such a step given there is a demand" from the Turkish people, he said.

Such a move is likely to cause anger among Christians and raise tensions between historic foes Turkey and Greece, both NATO members.

Greek Prime Minister Alexis Tsipras visited the Hagia Sophia in February.

Asked about the criticism, Erdogan said: "There are attacks targeting Al-Aqsa mosque," referring to the compound in Jerusalem known to Jews as the Temple Mount.

"Those who remain silent on this cannot dare to give advise to us on (Hagia Sophia)," he added.