Iran and Sudan both played instrumental roles in the 1998 attacks on the US embassies in Nairobi and Dar es Salaam, a federal judge in Washington has ruled.

The families of Kenyans and Tanzanians who worked in the embassies and who died in the bombings are therefore eligible to receive compensation from the governments of Iran and Sudan, US Judge John Bates decided.

Kenyans and Tanzanians employed by the US and who were injured in the attacks also qualify for damage payments, the judge found.

He referred the plaintiffs’ claims to a “special master” who will recommend how much payment should be made in each of the hundreds of cases. The total is likely to amount to billions of dollars.

Even though Iran and Sudan both refused to cooperate with the legal proceedings in Washington, the Kenyans and Tanzanians have a good chance of collecting payments, said Thomas Fay, one of the lead attorneys in the case.

Mr Fay, who directly represented several Tanzanian families, said his law firm is attaching liens to Sudanese and Iranian assets in the United States. Compensation can be paid from those holdings, the attorney explained, saying he believes the claims will be specified within the next few months.

Mr Fay noted that Sudan did pay damages to the families of those killed or injured in Al Qa’ida’s attack on the US destroyer Cole in 2000 when it was docked in Aden, Yemen.

US authorities have contended ever since the 1998 bombings in Nairobi and Dar that Sudan was culpable due to assistance its government had provided to the Al Qa’ida operatives who carried out the twin attacks, which took the lives of 212 Kenyans and Tanzanians as well as a dozen Americans.

Indications of Iran’s involvement had not been previously been detailed to the extent set forth in Judge Bates’ ruling.

“Iran provided substantial training and assistance to Al Qa’ida leading up to the embassy attacks in 1998,” Judge Bates wrote in his 45-page decision. “Prior to their meetings with Iranian officials and agents, Bin Laden and Al Qa’ida did not possess the technical expertise required to carry out the embassy bombings in Nairobi and Dar es Salaam.”

The judge based his findings on testimony and other evidence presented during a three-day hearing in October 2010.

Dr Matthew Levitt, a former US Treasury intelligence official and an expert on state sponsorship of terrorist groups, told the court that Al Qa’ida agents took part in meetings hosted by Sudan in the early- and mid-1990s. Also in attendance were Iranian officials and members of Hezbollah, a Lebanon-based Islamist group with close ties to Iran, Dr Levitt said.

Iran, through Hezbollah, provided explosives training to Al Qa’ida at camps in south Lebanon, he added.

After one such training session, “Al Qa’ida operatives connected to the Nairobi bombing, including a financier and a bomb-maker, returned to Sudan with videotapes and manuals ‘specifically about how to blow up large buildings,’” the judge’s decision states.

Sudan provided Al Qa’ida — including bin Laden himself for a time — with “safe haven” while the attacks were being planned, the ruling continues.

Sudanese intelligence and military officials provided “support and protection” for those directly involved in the bombings, the judge found. The assistance included “hundreds of Sudanese passports” as well as arrangements for Al Qa’ida members to “travel over the Sudan-Kenya border without restriction, permitting the passage of weapons and money to supply the Nairobi terrorist cell,” the ruling adds.