Embattled Maltese Prime Minister Joseph Muscat announced on Sunday he planned to step down, saying on state television he would ask his ruling Labour Party to start a process on January 12 to choose a new leader for the country.

Muscat’s government has been in crisis over an investigation into the murder of anti-corruption journalist Daphne Caruana Galizia. Calls for him to step down intensified after the probe led to charges on Saturday against a prominent businessman with alleged ties to government ministers and senior officials.

“I will write to the president of the Labour Party so that the process for a new leader is set for 12th January 2020. On that day I will resign as leader of the Labour Party. In the days after I will resign as prime minister,” Muscat said.

“Our country thus will start a short process of approximately a month for the Labour Party to choose a new leader and a new prime minister,” he added.

Thousands of people took part earlier on Sunday in an anti-government march in Valetta, the capital of the tiny Mediterranean archipelago, marching from the Parliament to the central courthouse in an event organised, among others, by activist group Repubblika, and led by members of the Caruana Galizia family.

The crisis over the Caruana Galizia murder probe grew after Yorgen Fenech, 38, was taken to a Valletta court late on Saturday and charged with complicity in the murder. He pleaded not guilty to that and other charges.

Fenech was charged after the government turned down his request for immunity from prosecution in return for revealing information about the murder plot and about alleged corruption involving Muscat’s former chief of staff Keith Schembri and former Tourism Minister Konrad Mizzi, among others, court filings showed.

Schembri and Mizzi resigned on Tuesday and Schembri was interrogated for two days by police before being released without charge. Schembri has denied any wrongdoing. Mizzi on Tuesday denied any business links with Fenech and any wrongdoing.

Critics are angry with Muscat for sticking by Schembri, an old friend since school, and including Schembri in security briefings on the murder investigation even after Fenech was identified both as a suspect in the murder and an associate of Schembri.

In his address on Sunday evening, the prime minister struck a defiant tone, saying that every day since Caruana Galizia’s murder he had shouldered responsibilities in “the interests of the case”. He added however that “some decisions were good while others could have been better made.”

Muscat has been in power since 2013, having won two general elections in a row, the last in 2017. His Labour Party had been expected to hold a leadership election in January.