Neighbouring India and Bangladesh have begun repatriating 185 incarcerated fishermen in a deal struck despite strained diplomatic ties, foreign ministry officials said.

Dhaka is handing over 95 Indian fishermen while New Delhi is releasing 90 Bangladeshis, with the handover set to be completed at sea by coastguard units.

New Delhi’s foreign ministry said the Indian fishermen were arrested after they “inadvertently” crossed into Bangladeshi waters.

Several Bangladesh fishermen were apprehended by Indian authorities in similar circumstances.

Some of the men have been held since September.

“The mutual exchange of fishermen and their vessels has been worked out keeping in mind the primarily humanitarian and livelihood concerns of fishing communities,” India’s foreign ministry said in a statement on Thursday.

Touhid Hossain, in charge of foreign affairs in Bangladesh’s interim government, said the exchanges of men would be completed on Sunday, Dhaka’s Prothom Alo newspaper quoted him as saying on Friday.

Two Bangladeshi fishing vessels detained in India and six Indian fishing boats held in Bangladesh will also be exchanged, Bangladeshi media reported.

Ties between the neighbours have been frayed since the August overthrow of autocratic Bangladesh ex-premier Sheikh Hasina in a student-led revolution.

Hasina’s iron-fisted rule was strongly backed by New Delhi and the 77-year-old remains in India, where she took refuge after her ouster.

Bangladesh has demanded her extradition to face charges of “massacres, killings, and crimes against humanity”.

The arrest of a prominent Hindu priest in Bangladesh on sedition charges in November has further added to tensions.

Indian Prime Minister Narendra Modi’s Hindu nationalist supporters have urged his government to take a more hardline stance towards Dhaka.