NEW YORK (CNN) -- New charges have been brought against four men whom U.S. authorities allege were involved in the August 7 bombings of U.S. embassies in Kenya and Tanzania -- including an allegation that the men were part of a decade- long international conspiracy to kill Americans.

Previously, three of the four -- Mohamed Sadeek Odeh, Mohamed Rashed Daoud Al-'Owhali and Fazul Abdullah Mohammed -- had been separately charged with eight counts of murder for the Americans who died in the attacks. But in an indictment unsealed Wednesday in federal court in Manhattan, more than 200 additional counts of murder were added.

U.S. Attorney Mary Jo White said the men would be charged for "each and every victim of the embassy bombings." The attacks in Nairobi and Dar es Salaam killed 258 people.

In addition, the three suspects, along with a fourth man, Wadih el Hage, were formally linked together for the first time with a charge that they were part of a conspiracy to kill Americans, masterminded by Osama bin Laden, an elusive billionaire whom U.S. officials accuse of heading an international terrorist network.

The indictments say the conspiracy began in 1989 and includes such activities as organizing terrorist training camps, recruiting U.S. citizens to help buy weapons and explosives and establishing headquarters and businesses in Sudan to aid the conspiracy.

In addition to the attacks at the embassies in eastern Africa, prosecutors allege that American military personnel stationed in Saudi Arabia and Somalia were also targeted by the conspiracy.

People trained at a camp run by bin Laden participated in a 1993 attack that killed 18 U.S. Army personnel in Mogadishu during a U.S. peacekeeping mission in Somalia, the indictment says.

El Hage -- a Texas resident who is so far the only U.S. citizen charged in the attacks -- had already been charged with eight counts of perjury for allegedly lying to a federal grand jury and to law enforcement agents about his relationship with bin Laden. His attorney said he was not surprised by the new indictment.

"I thought at some point they would bring additional charges," Bruce McIntyre said.

If convicted of the charges against them, Odeh, Al-'Owhali and Mohammed could face the death penalty. El Hage faces a maximum of life imprisonment.

Mohammed, whose was previously indicted under the alias Haroun Fazil, is still at large. The other three men are being held without bond in a New York jail and are expected to be arraigned on the new charges during a court appearance Thursday.