Colombo, Oct 29 (IANS): Former Sri Lankan strongman Mahinda Rajapaksa assumed duties as the country's new Prime Minister on Monday following the ouster of his predecessor Ranil Wickremesinghe by President Maithripala Sirisena last week.

Rajapaksa assumed charge at the Prime Minister's Office in the morning, the Daily Mirror reported. A faction of the new Cabinet was expected to take oaths before the President later in the day.

A political crisis erupted in the island country after Sirisena sacked Wickremesinghe on Friday and replaced him with former President Rajapaksa.

The President, in a letter sent to Wickremesinghe, had said he had been removed after the Sirisena-led United People's Freedom Alliance (UPFA) quit the national coalition government.

The coalition government consisted of the UPFA and the United National Party (UNP) led by Wickremesinghe.

Sirisena on Saturday suspended Parliament till November 16.

Meanwhile, UN Secretary-General Antonio Guterres expressed concern over the deepening crisis and called for restraint from all parties in the island country.

His remarks followed Sunday's shooting by a bodyguard of a former minister at a crowd in which one person was killed and two were injured.