An Israeli court issued a sweeping rejection Tuesday of a lawsuit filed by the family of an American activist killed by a military bulldozer nine years ago, ruling that the death of Rachel Corrie was an accident for which she was responsible and that soldiers had acted with neither intent to harm nor criminal neglect.

Corrie’s family slammed the verdict and said they would appeal to the Supreme Court.

The US State Department called Corrie’s death “tragic” on Tuesday.

“We understand the family’s disappointment with the outcome of the trial,” said State Department spokeswoman Victoria Nuland. She did not say if the Obama administration shared that sentiment.

Corrie, a 23-year-old native of Olympia, Washington, was crushed to death on March 16, 2003, by a military armored bulldozer clearing vegetation in a combat zone along the Gaza-Egypt border.

Corrie and other pro-Palestinian activists had confronted two bulldozers and a small infantry contingent guarding the vehicles in an attempt to halt what the activists believed was an impending home demolition. Corrie was in front of the bulldozer’s blade trying to block the vehicle when she was killed.

Corrie’s family sued Israel over her death, charging that soldiers had either killed her intentionally or acted with reckless neglect. They asserted that the Israeli military was responsible for Corrie’s life even though she had knowingly placed herself in danger to thwart a military operation.

They were seeking a symbolic $1 in damages and legal fees.

Judge Oded Gershon rejected all of the family’s claims. “This was a very unfortunate accident and not an action undertaken with intent,” Gershon said Tuesday in a courtroom packed with spectators and reporters.

“The deceased put herself into a dangerous situation. She stood in front of a large bulldozer in a place where the operator could not see her. Even when she saw the mound of earth approaching her she did not distance herself as a reasonable person would have done,” he said.

Corrie’s death, he ruled, was “the result of an accident she brought upon herself.” The family’s claim that her death was intentional was “baseless,” he said.

The activist’s mother, Cindy Corrie, said the family was “deeply saddened and deeply troubled” by the ruling.

“I believe this was a bad day not only for our family but for human rights, for humanity, for the rule of law, and also for the country of Israel,” she said at a press conference held by the family after the ruling.

She called the Israeli court system “a well-heeled system to protect the Israeli military and the soldiers who take action in that military and provide them with impunity.”

“The state has worked extremely hard to make sure that the truth about what happened to my daughter is not known and those responsible will not be held accountable,” she said.

The Corries’ lawyer, Hussein Abu Hussein, said the family would appeal the lower court’s ruling to the Supreme Court.

Corrie was clearly visible because of a bright yellow jacket she was wearing, he said, calling her an “American peace activist who only wanted to protest house demolitions and the great injustice against residents of Gaza.”

After her death, Corrie became a hero for opponents of Israel, the subject of a play, and probably the best-known victim of the violence of the second Palestinian Intifada, which claimed more than 6,500 lives. A foundation set up by her family in her honor advocates for an anti-Israel boycott.

The bulldozer operator, an army reservist who was identified only by his first initial, Y., testified in court that because of the armored vehicle’s restricted field of vision he did not see the American.

In Tuesday’s decision, the court accepted that explanation. An earlier military investigation also cleared the soldiers of wrongdoing, and the judge said that investigation “was not flawed in any way.” The Israeli forces on the ground were in “deadly danger” and had acted properly, he said, warning the activists to leave the area in a confrontation that began several hours before Corrie’s death. They ignored the warning.

Corrie was a member of the International Solidarity Movement, a pro-Palestinian group that has sent Western volunteers to interfere with Israeli military activities in Gaza and the West Bank. The area of the incident, in southern Gaza at the town of Rafah, was one of the most dangerous spots during the peak years of Israeli-Palestinian violence nearly a decade ago.

The commander of the troops on the scene, an infantry major, testified last year that the activists had ignored repeated warnings to leave and were endangering his troops. “It was a war zone,” he told the court. The judge repeated that description in Tuesday’s decision, saying that from the outbreak of violence in September, 2000, and until the day of Corrie’s death Israeli forces counted some 6,000 hand grenades thrown at them in the area, as well as 1,400 shooting attacks, 150 explosive devices, 200 anti-tank rockets and more than 40 instances of mortar fire.

Hearings in the trial began in 2010.

In one of the trial’s most dramatic moments last year, those present in the courtroom heard a recording from the military radio network during the incident, including the operator’s terse report at 5:05 p.m.: “I hit someone.”

Corrie, badly wounded, was rushed to a Gaza hospital. She died a short time later.