Amid the crisis, Rajapaksa's whereabouts remain unknown.
Protesters who overran Sri Lanka President Gotabaya Rajapaksa's official residence in Colombo discovered a high security bunker in the compound.
Rajapaksa on Saturday fled his official residence shortly before angry protestors overran the compound and his office nearby.
The bunker was found hidden by a fake cupboard. It goes underground and is accessed by an elevator. The heavy door of the bunker could not be opened, reports said.
The island nation, gripped by an unprecedented economic crisis, saw hundreds of thousands of protesters on the streets around the Presidential Palace, demanding Rajapaksa's resignation for his government's mismanagement of the crisis.
After storming the Palace gates, protesters barged into Rajapaksa's residence and were seen exploring the compound in numbers. Some were seen on Rajapaksa's bed while some were caught on camera jumping into the swimming pool in the compound. Many were even seen lounging in his living room.
Amid the crisis, Rajapaksa's whereabouts remain unknown.
The President's only communication has been with the Parliament Speaker Mahinda Yapa Abeywardena.
Meanwhile, Prime Minister Ranil Wickremesinghe's residence was set on fire by protesters on Saturday.
"Protesters have broken into the private residence of Prime Minister Ranil Wickremesinghe and have set it on fire," said the Lankan Prime Minister's Office in a statement.
Sri Lanka, a country of around 22 million people, had announced in April that it was suspending nearly USD 7 billion foreign debt repayment due for 2022 out of about USD 25 billion due through 2026.