In this story:

• Texas: Stay of execution
• California: 'No one ever informed my client'
• Backlash against Americans abroad?
• Related stories and sites

LOS ANGELES (CNN) -- Dozens of citizens from other countries who are on death row in the United States are being held illegally, say critics who accuse states of violating an international treaty that allows people charged with a crime to contact their own government for help.

"It's apparent that the United States is routinely violating this," says Erwin Chemerinsky, a law professor at the University Southern California.

The State Department, meantime, has taken steps -- including the posting of a booklet on its Web site -- to ensure that local U.S. authorities are aware of the treaty and comply with its legal obligations.

The little-known controversy became more publicized earlier this month when the U.S. Supreme Court issued a stay of execution for Joseph Stanley Faulder, a Canadian facing a lethal injection in Texas for a 1975 murder.

Faulder's attorney, death penalty opponents and the Canadian government contend that Canadian authorities should have been told of his arrest and detention, under terms of the Vienna Convention on Consular Relations.

Under that 1969 treaty, Texas authorities should also have informed Faulder of his right to contact the Canadian government for help.

The United States is among at least 144 nations that have agreed to the treaty, according to the Death Penalty Information Center.

The Washington-based organization estimates Faulder is among about 70 non-American inmates in various U.S. states who are under death sentences.

One of them, a Thai named Jaturun Siripongs, also claims his rights were violated. Now on California's death row, Siripongs was convicted of a 1981 murder and has been sentenced to die by lethal injection on February 9.

"No one ever informed my client that he had the right to speak with the Thai consulate in Los Angeles," said defense attorney Linda Schilling. "Had he been so informed, he would have said, 'Yes, I want help.'"

Prosecutors say the Thai consulate was aware of what was going on.

Schilling told CNN she would be happy if Siripongs could serve a life term with no possibility of parole in his native Thailand.

Human rights groups say U.S. failure to observe the treaty might lead to abuse against Americans arrested abroad, a position also taken by the State Department.

"If we don't do all we can to... tell foreign nationals here that they can have consular access, then American citizens around the world... could be missing out on important opportunities to defend themselves through such notification of our consulates and embassies," said State Department spokesman James Rubin.

U.S. Secretary of State Madeleine Albright was among those who sought a reprieve in the Faulder case.

Texas Gov. George W. Bush, however, was unmoved. "People can't just come in our state and cold-blood murder somebody," Bush said. "That's unacceptable behavior, regardless of their nationality."

Correspondent Charles Feldman and The Associated Press contributed to this report.