Journalists in Malta have taken to streets to insist they "will stand up to intimidation" as the sons of slain investigative journalist Daphne Caruana Galizia called on the island nation's prime minister to quit.

Hundreds of news industry workers on Thursday gathered outside the parliament in the capital, Valletta, holding up front pages and placards splattered in blood-red paint to protest the murder of Caruana Galizia, a well-known reporter exposing corruption in Malta who was killed in a car bomb attack on Monday.

"This is one of the most despicable acts ever carried out in this country. Nobody deserves to die for exercising the right to speak," said Herman Grech, online editor at The Times of Malta, reading a common statement on the industry's behalf.

"We stand here today to give hope to society. This attack on one of us will not stop us from shining a light where others want darkness. The attack on one of us will not muzzle us. The attack on one of us will not stop us from fulfilling our role as a watchdog to the institutions. We will stand up to intimidation."

The statement urged the government to promote press freedom and stop tolerating incitement against the free media.

"We will not stop. We will not be afraid," Grech concluded, to heavy applause.

Carrying a red-spattered Maltese flag, the protesting journalists also marched to the Courts of Justice, where an application was filed calling for the investigation into Caruana Galizia's murder to ensure her sources are protected.

Malta's newspapers, broadcasters and online media, including the country's many politically partisan outlets, will all carry a common message about press freedom on Sunday.



"We have agreed on a national campaign under the slogan: 'the pen conquers fear'," Norma Saliba, chair of the Institute of Maltese Journalists, told AFP news agency.

'Show political responsibility and resign'

The murder stunned Malta and caused international shock over whether the Mediterranean island is becoming a cesspit of corruption against the backdrop of an economic boom which some see as having allowed both organised crime and a kickbacks culture to flourish.

Caruana Galizia, 53, had used her widely read blog, Running Commentary, to highlight numerous cases of suspected corruption, including several scandals implicating the inner circle of Prime Minister Joseph Muscat which had left her facing a string of legal suits.

Following the allegations, the Labour leader called, and won, an early election in June.

Muscat, who was in Brussels on Thursday, has ruled out quitting and has vowed, with the help of FBI investigators, to bring to justice those responsible for killing a reporter he has described as his "greatest adversary".

On Wednesday, Muscat told parliament that the government would put up a "substantial and unprecedented reward" for information leading to a conviction over the assassination.



Her sons Matthew, Andrew and Paul said on Thursday that the government was putting up a million euro ($1.2m), but vowed they would not bow to pressure to endorse the idea.



"We are not interested in a criminal conviction only for the people in government who stood to gain from our mother's murder to turn around and say that justice has been served," they said.



"The prime minister asked for our endorsement. This is how he can get it: show political responsibility and resign."

Huge blast

Investigators, meanwhile, were looking at similarities with other car bombings in Malta over the last two years - six in all including Caruana Galizia's. None have been solved.

Caruana Galizia had just driven away from her home in Mosta, a town outside Malta's capital of Valletta, when the exploded, sending the vehicle's wreckage spiralling over a wall.

The force of the blast reduced her car to pieces and catapulted the journalist's body into a nearby field, witnesses said. She leaves behind a husband and three sons.

Former police commissioner John Rizzo told the Malta Independent that it appears that mobile detonated explosives were used in each of the six bombings since the start of 2016, which caused four deaths and two serious injuries. The previous victims were all known to police, the paper said.

"Very few people could construct such a bomb. Instructions may be obtained online, but building such a device would still require a certain degree of skill," Rizzo said.

Investigators have not publicly identified which explosives were used in the journalist's murder, but experts say any military grade explosives, like Semtex, are not available in Malta and would have had to be brought in from abroad.