Former Sri Lankan Petroleum Minister Arjuna Ranatunga was arrested on Monday in connection with a shooting incident at the Ceylon Petroleum Corporation, Daily Mirror reported. Colombo’s Crime Division personnel arrested the former minister in Dematagoda.

One person died and two were injured on Sunday when a mob attempted to surround Ranatunga and his security personnel opened fire.

Ranatunga was a minister in the Cabinet dissolved by President Maithripala Sirisena on Saturday, a day after he sacked his former ally Ranil Wickremesinghe as the prime minister and replaced him with former President Mahinda Rajapaksa. Wickremesinghe, who Parliament’s Speaker Karu Jayasuriya recognised as the prime minister on Sunday, has said he will not resign and called Sirisena’s move “illegal and unconstitutional”.

On Sunday, the Sri Lankan police said that Ranatunga’s bodyguards opened fire at a mob of people, allegedly loyal to Sirisena, after they tried to take the former minister hostage while he was trying to enter his office at the Ceylon Petroleum Corporation. One of Ranatunga’s security officers was arrested at the Ceylon Petroleum Corporation premises.

It was the first instance of serious violence that has been reported from the country since it plunged into a constitutional and political crisis last week.

Petroleum trade unions had launched a strike to protest the Ceylon Petroleum Corporation employee’s death, Colombo Gazette reported. The trade unions had demanded Ranatunga’s arrest.

Sri Lanka has been facing a constitutional crisis since Sirisena’s United People’s Freedom Alliance withdrew from the coalition government. Last week, Sirisena accused Wickremesinghe’s United National Party of not taking seriously an alleged plot to assassinate him and former Defence Secretary Gotabaya Rajapaksa, the brother of Mahinda Rajapaksa.

On Saturday, Sirisena suspended Parliament till November 16, purportedly in an effort to buy time so that he and Rajapaksa could prove their majority. Rajapaksa and Sirisena’s parties together have only 95 seats, short of a majority in the 225-member house. Wickremsinghe’s party has 106 seats on its own, however, it is also seven short of the majority.

Sirisena was chosen to be president in 2015 largely because of votes from Wickremesinghe’s party, ending Rajapaksa’s almost decade-long rule. However, both the ruling parties suffered heavy defeats in the local elections in February. Later, Sirisena aides supported a no-confidence motion against Wickremesinghe, who survived the vote because a majority of legislators backed his government.