India 'deeply concerned' at Bangladesh crisis: Foreign minister

India's foreign minister said on Tuesday he was "deeply concerned till law and order is visibly restored" in neighbouring Bangladesh, a day after the ouster of prime minister Sheikh Hasina.

Foreign minister S. Jaishankar also gave the first official confirmation Hasina was in India, where she fled on Monday as protesters stormed her palace.

"We... will naturally remain deeply concerned till law and order is visibly restored," Jaishankar told parliament.

New Delhi has kept a wary eye on the fall of Hasina, who pursued a delicate balancing act of enjoying support from India while maintaining strong relations with China.

Bangladesh army chief General Waker-Uz-Zaman announced on state television on Monday that Hasina had resigned and the military would form an interim government.

"In the last 24 hours, we have also been in regular touch with the authorities in Dhaka," Jaishankar said.

Hasina fled by helicopter to India, arriving at a military airbase near New Delhi.

A top-level source said she wanted to go on to London but calls by the British government for a UN-led investigation into "unprecedented levels of violence" put that in doubt.

"Our understanding is that after a meeting with leaders of the security establishment, Prime Minister Sheikh Hasina apparently made the decision to resign," Jaishankar said.

"At very short notice, she requested approval to come for the moment to India. We simultaneously received a request for flight clearance from the Bangladesh authorities. She arrived yesterday evening in Delhi."

India shares a border with Bangladesh of more than 4,000 kilometres.

Social media users shared photos of protesters ransacking Rajapaksa's official residence alongside Bangladeshi protesters storming Hasina's palace on Monday.