By Jane Sutton

GUANTANAMO BAY U.S. NAVAL BASE, Cuba (Reuters) - Watching the U.S. military tribunal hearings for the men accused of plotting the September 11 attacks can be gut-wrenching for the victims' families, some of whom are still receiving their relatives' newly identified remains thanks to improved DNA testing unavailable a decade ago.

Some family visitors have said they are galled to see American lawyers, including some U.S. military lawyers paid with their tax money, fighting vigorously in court to safeguard the rights of what one called "these monsters."

Family visitors attending this week's session at the Guantanamo Bay U.S. Naval Base in Cuba, most of them the parents of Cantor Fitzgerald brokers who died in the World Trade Center, had an unprecedented private meeting on Sunday with the defense lawyers, sharing their painful stories and in some cases, crying together.

"They were truthful, they were honest and they expressed their pain. I myself learned a great deal from them," said James Connell, a civilian defense lawyer for Pakistani defendant Ali Abdul Aziz Ali.

The lawyers explained their role in the adversarial court process and said it was their duty to provide a zealous defense.

"I am proud of our nation for doing that but it does hurt," Matthew Sellitto said after watching two days of hearings this week in the U.S. military tribunal of five men charged with plotting to slaughter his 23-year-old son, also named Matthew, and 2,975 other people.

He said the legal process was necessary to build a verdict that would stand up on appeal.

His wife, Loreen Sellitto, said it was difficult "to see these fellow Americans defending people ... who started out that day not to kill my son but to kill Americans en masse."

More than 11 years later, Sellitto and his wife sat behind a glass wall in the spectator gallery in the courtroom.

They listened as the defendant Ali, asked to phone home. Ali, a Pakistani, had learned in October that his father died, and he wanted to make a condolence call to his mother, Ali's lawyer told the court.

The judge said he empathized but did not think he had authority to order such a call. That was fine with Matthew Sellitto.

"I wouldn't have given him that right, no," Sellitto said. "He made his choice. Now he's got to live with that choice."

Joyce Woods, a Pearl River, New York, woman whose 26-year-old son James also worked at Cantor Fitzgerald, said she felt sorry for Ali's mother but would not have allowed the call either.

"I didn't get to talk to my son. I didn't get the opportunity to have one last phone call," Woods said. "I cannot be generous enough to say 'yes, you can talk to your mother but my son cannot talk to me.'"

Relatives of those killed in the September 11 attacks are chosen in a Pentagon lottery to travel to the remote Guantanamo base to attend pretrial hearings for the alleged conspirators and some may eventually testify in their trial on charges that include attacking civilians, terrorism and hijacking.

The relatives who make the trip often disagree about whether the trials for the September 11 suspects should be held in New York or Guantanamo, in federal courts or in military tribunals. They express little doubt the defendants will be convicted but have varying opinions about whether they should be executed.

Loreen Sellitto said the appropriate sentence would be life in prison with their every move dictated by "the culture they tried to destroy. Americans would control when they eat, when they pray, when they exercise."

And whether they ever make another phone call.

(Editing by David Adams, Tom Brown and Mohammad Zargham)