Speaking to reporters, the prime minister said a joint team of police, military and security services made the arrests following a near seven-week investigation carried out with help from the FBI, Europol and Finnish intelligence.

Caruana Galizia’s murder triggered an outpouring of grief on Malta and an international outcry over press freedom. It also turned an unflattering spotlight on the EU country’s problems with corruption and organised crime, both seen as having flourished against the backdrop of a booming economy.

Muscat announced the arrest of eight of the suspects in a statement and then added in a tweet, that a further two had been detained.

The statement said the suspects had been arrested on the basis of “reasonable suspicion in connection with involvement in the murder” of Caruana Galizia. All the suspects were Maltese nationals, it said, noting that some were “known to police”.

Under Maltese law, they can be interrogated for 48 hours before a decision on whether to prosecute them has to be made.

Muscat would not divulge if the suspects included the alleged perpetrators of the assassination, or those suspected of commissioning it.

Nor would he comment on the suspected motive, saying he did not want to go into any detail for fear of prejudicing a potential trial.

The premier, who had described the slain journalist as his biggest adversary, reiterated his commitment to bringing her killers to justice.

“As I stated as soon as I learned about this barbaric act, we will leave no stone unturned to get this case solved,” he said. “I am committed to doing so more than ever.”

Muscat’s Labour Party government had offered a €1 million (US$1.2 million) reward for information leading to a conviction of Caruana Galizia’s killers.

Her sons had denounced the reward as a publicity stunt and called on Muscat to resign over the failings in the police and judiciary that contributed to their mother’s death and his attempts to silence her through legal suits when she was still alive.

The family have repeatedly expressed concern that her death will be explained away as a criminal murder and that any connection with her revelations about the island’s political elite will be swept under the carpet.

In her final post on Running Commentary, the widely read blog she had written since 2008, Caruana Galizia voiced despair over the cronyism and sleaze she saw engulfing her island nation.

“There are crooks everywhere you look now. The situation is desperate,” she wrote minutes before she died in a blast so powerful her car was blown to pieces and her body was catapulted into a nearby field.

Friends subsequently revealed that she had feared she would be assassinated but had been reluctant to accept police protection that would have restricted her reporting activity.

A significant part of that had involved exposing what the massive Panama Papers data leak revealed about corruption at the highest levels of Maltese government.

Earlier this year, online news site Politico included the journalist on a list of 28 public figures “shaping, shaking and stirring Europe,” describing her as “a one-woman WikiLeaks”.

She is survived by her lawyer husband, Peter, and three sons.