Leading Democrats voiced horror and called for a rethink of the US alliance with Saudi Arabia on Wednesday after mass executions, while President Donald Trump's administration expressed only indirect concern.
Saudi Arabia on Tuesday beheaded 37 citizens, nearly all from its Shiite minority, with one crucified after death and the UN saying that at least three were minors when charged.
Senator Bernie Sanders, who is seeking the Democratic nomination for president, said the mass execution "underscores how urgent it has become for the United States to redefine our relationship with the despotic regime in Saudi Arabia."
Sanders said the United States should "show that the Saudis do not have a blank check to continue violating human rights and dictating our foreign policy."
Senior Democratic Senator Dianne Feinstein said she had already called for the United States to "reconsider our relationship with Saudi Arabia" after the October killing and dismembering of US-based journalist Jamal Khashoggi in the kingdom's Istanbul consulate.
"These latest reports reinforce my concerns. We can't look way from Saudi Arabia's increased use of executions, particularly when so many questions surround the validity of the trials," she tweeted.
There was no immediate reaction from Trump, who vowed to preserve warm relations with Saudi Arabia even after Khashoggi's murder.
Asked about the executions, the State Department said that Secretary of State Mike Pompeo has raised human rights with Saudi leaders in "every instance" when there were concerns.
"We urge the government of Saudi Arabia, and all governments, to respect and protect human rights and fundamental freedoms, ensure fair trial guarantees, transparency, freedom from arbitrary and extrajudicial detention, and freedom of religion and belief," a State Department spokeswoman said.
The spokeswoman did not comment directly on the executions but said the United States opposed capital punishment in cases when the defendant was a minor at the time of arrest of alleged offense.
The Trump administration has hailed Saudi Arabia as a valuable partner due to its extensive purchases of US weapons, vast oil reserves and shared hostility to Iran.
The United States is the only Western nation that still practices capital punishment.