Seven may have died in Madrid raid
Judge orders two Moroccans jailed in March 11 probe
Train attack suspects among those killed by blast in Madrid suburb.
MADRID, Spain -- Forensics experts say as many as seven suspected Islamic terrorists linked to the Madrid train bombings may have been killed in an explosion as police raided their hideout Saturday.
Initial reports said up to six suspects were killed in the blast as police surrounded an apartment in the Madrid suburb of Leganes.
A Spanish police officer taking part in the raid was also killed in the blast.
Four of the suspects who died in the explosion have been identified.
They include two alleged ringleaders of the March 11 attacks in Madrid, which killed 190 people and wounded more than 1,800.
Up to three other accomplices have not been identified because the remains are badly mangled from the explosion, the forensics experts said.
A spokesman for Spain's National Court said the suspects had explosives, cash and also documents indicating they planned to carry out further attacks.
Meanwhile, a Spanish judge ordered two Moroccan men jailed Wednesday on charges they belonged to or conspired with an armed band of terrorists.
The decision to jail the men brings to 17 the number of people charged so far in the investigation of the March 11 attacks.
Of those total charged, 13 are Moroccans.
Most of those who have been arraigned to date have been charged in the bombings, but others have been released, some without charges. At least one suspect is required to report daily to police or court authorities.
As millions of Spaniards leave cities for the traditional Easter Week holiday, the country remains on high alert, with security reinforced at transportation hubs and strategic installations like ports, nuclear power plants and dams.
A letter faxed to a Spanish newspaper on Saturday, purportedly from an Islamic group linked to al Qaeda, threatened to turn Spain "into an inferno" if its troops are not withdrawn from Iraq and Afghanistan.
Investigators are analyzing the letter.
-- CNN's Madrid Bureau Chief Al Goodman contributed to this report