Hunt for killer of public order ministry aide

The bomb was hidden in a cardboard box mailed inside a padded envelope and consisted of half a kilo (one pound) of gunpowder and ammonium nitrate, a police source said.

A bomb disposal unit also found the remains of a battery and a hook that was used to activate the explosives when the parcel was opened, the source added.

It was apparently addressed to Chryssohoidis, who had recently married, but a police source said it was impossible to confirm for the moment what was written on the slip.

The parcel had originally been mailed on Tuesday from the working class district of Kypseli to Chryssohoidis' political office in central Athens, and was brought to the ministry by a member of his staff, a police source said.

The victim George Vassilakis, 52, was a close associate of the minister for the past decade and was tasked with inspecting Chryssohoidis' correspondence. The minister, who has led a crackdown on far-left groups responsible for other attacks, was just a few metres (yards) away when the bomb went off and was unhurt.

Greek Prime Minister George Papandreou told parliament on Friday that the perpetrators of the "heinous terrorist act" would not win.

"Yesterday we witnessed an incident of blind and inhuman violence," he said.

"A family man fell victim to a heinous terrorist act."

"The murderers should know that they will fail because they have the state and all of society against them. Our society cannot be terrorised," the prime minister added.

The explosion happened as the country battles a major debt crisis. The Socialist government's austerity programme has provoked widespread strikes and protests.

"It is nearly impossible for someone carrying a bomb to get into the ministry, but to get a packet in is easier," said police union official Vassilisi Doumas, speaking on Flash radio.

He said the booby-trapped package could have been carried into the building by a member of staff, a possibility also raised by Greek media.

Police spokesman Thanassis Kokkalakis admitted there could have been "negligence" by the building's security. He told Sky radio there was no specialist bomb detecting equipment at the entrance.

But he added that he "could not believe" there had been internal help with the attack.

"We need to understand how the parcel entered the building before we can pick up the trail," Kokkalakis told AFP.

"We are looking for the weak link in our security," he said.

A police source told AFP there are two security checks at the ministry entrance.

Chryssohoidis was clearly in shock when he paid tribute to his assassinated aide after the attack.

"We are not afraid, we will continue to fight," he told journalists at the ministry's entrance. "Personally, I have lost a precious and dear colleague."

Chryssohoidis was in the same post when the November 17 militant group was broken up in 2002. It had been blamed for about 20 assassinations since 1975.

He had vowed to reform a police force often accused of lacking professionalism and was given credit for the detention of six alleged members of the Revolutionary Struggle group in April.