Image caption Aldawsari's lawyers acknowledged he had intent, but never took the "substantial step"

A Saudi student who plotted to attack the Texas home of ex-President George W Bush and other targets has been sentenced to life in jail.

A judge said he had no doubt Khalid Aldawsari, convicted in June of trying to use a weapon of mass destruction, was serious about his plans.

The FBI found bomb-making materials in the 22-year-old's Lubbock, Texas home just before his February 2011 arrest.

Nuclear power plants and hydroelectric dams were also on his list of targets.

At the sentencing in Amarillo, Texas, Judge Donald Walter said: "The bottom line is that but by the grace of God there would be dead Americans.

"You would have done it. In every step, it was you all alone."

'Time for jihad'

The investigation into Aldawsari began when his $435 (£273) purchase from a chemical company raised suspicions.

I am sorry for these bad actions, but none of these bad actions did harm to the United States Khalid Aldawsari

Investigators said he had ordered the toxic chemical phenol, which can be used to make explosives, telling the supplier he wanted it for "off-campus, personal research".

The supplier became suspicious and reported the contact to the FBI. Aldawsari later cancelled the order, the justice department said.

He eventually succeeded in buying nearly eight gallons (30 litres) of concentrated nitric acid and three gallons of concentrated sulphuric acid, prosecutors said.

Just before he was arrested, federal agents secretly searched his apartment and found explosive chemicals, wiring, a hazardous-materials suit and clocks, along with videos showing how to make the chemical explosive TNP.

The FBI found evidence that Aldawsari had researched targets, including the Dallas home of Mr Bush, which the student referred to as "Tyrant's House".

Aldawsari wrote in a journal entry: "And now, after mastering the English language, learning how to build explosives and continuous planning to target the infidel Americans, it is time for Jihad."

'Doll-bomb research'

Aldawsari apologised at Tuesday's hearing: "I am sorry for these bad actions, but none of these bad actions did harm to the United States."

During the trial, defence lawyers acknowledged the student had intent, but they said he never took a "substantial step" to carry out an attack.

FBI bomb experts said the amounts of chemicals Aldawsari gathered would have yielded almost 15lb (7kg) of explosive - about the same amount used per bomb in the 2005 London subway attacks.

Other potential targets Aldawsari researched included the homes of three former soldiers who were stationed at Abu Ghraib prison.

His internet searches also suggested he was considering hiding explosives in children's dolls or targeting a nightclub with a bomb in a backpack.

He came to the US legally in 2008, initially studying chemical engineering at Texas Tech before transferring to South Plains College to study business. A Saudi industrial company was paying his tuition and living expenses.