Bangkok: The Philippine military has discovered Islamic State sent more than $US1.5 million ($1.9 million) to finance the siege of the southern Philippine town of Marawi which experts say was a propaganda windfall for the Middle East-based terror group.

Early in the 154-day blocade there were reports bundles of money had been found in buildings around town, but Philippine military chief Eduardo Ano on Tuesday did not elaborate.

Philippine troops return to their deployment after attending the ceremony where President Rodrigo Duterte declared the liberation of Marawi complete. Credit:Bullit Marquez

In an interview he said as well as receiving money from IS, the Marawi militant local leaders used the 2014 seizure of the Iraqi city of Mosul as a blueprint for takeover.

"Every day they watched videos of IS in Mosul," said General Ano of the siege leaders, including Isnilon Hapilon, one of the US's most-wanted terrorists who was killed last week.