A petition from dozens of authors was sent to President Obama on Wednesday asking him to press Saudi Arabia to pardon a prominent poet condemned to beheading and a blogger punished with prison and flogging.

The petition, organized by the PEN American Center, a group that promotes free expression, threw a spotlight on what critics call the Obama administration’s reluctance to antagonize the religiously strict Saudi kingdom, a partner in the conflict in Syria and the broader struggle to combat violent Islamic extremism.

The administration has not overtly challenged the Saudis on a number of policies and judicial practices that are generally regarded as oppressive, like systematic discrimination against women, severe curbs on free expression and punishments that include decapitation.

“The United States has been hesitant to call out the Saudis on human rights issues,” Suzanne Nossel, executive director of the PEN American Center, said in a telephone interview about the petition. “You can see all the reasons for hesitation,” she said, but they are outweighed by “the gravity of these two cases.”

There was no immediate reaction from the White House to the petition, which Ms. Nossel said had been emailed.

Signers included more than 60 prominent artists in the literary world, including Michael Chabon, Ha Jin, Jessica Hagedorn, Paul Muldoon, Zia Haider Rahman and Elissa Schappell.

The petition concerns the fate of Ashraf Fayadh, 35, a Palestinian poet who has always lived in Saudi Arabia, and Raif Badawi, 31, a Saudi writer and activist who managed an online forum called Free Saudi Liberals.

Mr. Fayadh was sentenced on Nov. 17 to death by beheading for apostasy, based on poems he published years earlier that the Saudi authorities deemed atheistic and blasphemous.

Mr. Badawi was arrested three years ago and convicted of insulting Islam and promoting unacceptable thoughts electronically. He was sentenced to 10 years in prison and 1,000 lashes to be delivered in 50-lash installments, but that part of the punishment was suspended in January after the first lashing, which provoked an international outcry and, according to his wife, Ensaf Haidar, nearly killed him.

Ms. Haidar, who now lives in Canada with their three children, has said Mr. Badawi was recently moved to an isolated prison intended for convicted felons whose appeal remedies have been exhausted. The PEN petition called the relocation “a troubling sign that any hope he would be pardoned has been dashed.”

The petition coincided with a ceremony honoring Mr. Badawi by the European Parliament in Strasbourg, France, which bestowed on him its Sakharov human rights prize this year. Ms. Haidar accepted the award there on his behalf.

Saudi Arabia has faced a torrent of increasingly negative outside publicity over its heavy use of the death penalty and its harsh treatment of advocates of a more open and tolerant society. The two cases cited by the PEN petition are regarded by advocates as especially egregious.

The petition said the severity of the sentences against Mr. Fayadh and Mr. Badawi, “rendered for crimes that are not crimes, cannot go unremarked upon any longer by the president of the United States.”

It asked Mr. Obama to urge King Salman, the Saudi ruler, to “grant them unconditional and immediate release.”