Hamas released a video on Wednesday apparently showing Hersh Goldberg-Polin, an Israeli American dual citizen who has been held hostage since the Oct. 7 terrorist attack on Israel. It appeared to be the first time that Mr. Goldberg-Polin, who was grievously injured in the attack, has been shown to be alive since his captivity began.

It is not clear when the video was filmed, but in it Mr. Goldberg-Polin, who was 23 when he was abducted, says he has been held hostage for nearly 200 days, suggesting the video was made recently. He also wishes his parents a happy holiday, which may be a reference to the weeklong Passover holiday currently being celebrated.

Mr. Goldberg-Polin’s parents later released a videotaped statement saying they were relieved to see their son alive but worried about his health, along with the health of the scores of other hostages still believed to be held in Gaza.

“We are here today with a plea to all of the leaders of the parties who have been negotiating to date — this includes Qatar, Egypt, the United States, Hamas and Israel — be brave, lean in, seize this moment and get a deal done to reunite all of us with our loved ones and end the suffering in this region,” his father, Jonathan Polin, said. His mother, Rachel Goldberg-Polin, urged her son to “stay strong, survive.”

In a video message, Rear Adm. Daniel Hagari, the spokesman for Israel’s military, told Mr. Goldberg-Polin’s family that Israel would do all it could to “bring your son Hersh and all our hostages back home.”

“This is an urgent call for action. We will leave no stone unturned in our efforts to find our hostages,” he said.

Mr. Goldberg-Polin was attending the Tribe of Nova music festival in Re’im, Israel, when Hamas gunmen attacked, killing hundreds. He lost part of his arm while defending an emergency shelter alongside his friend Aner Shapira, who was killed, according to survivors of the attack.

Rights groups and international law experts say that a hostage video is, by definition, made under duress, and the statements in it are usually coerced. Israeli officials have called the videos a form of “psychological warfare,” and experts say their production can constitute a war crime.

The circumstances of how the video were filmed were unclear, and the footage appears to have been edited. It was released on Hamas’s social media channels at about 5 p.m. in Israel.

Mr. Goldberg-Polin refers several times to his need for medical attention and shows his injured arm to the camera. The October attack left him “struggling to survive with serious injuries all over my body,” he says in the video, adding that during his captivity he has been “without water, food or sun and without treatment I have needed for so long.”

He also criticizes Prime Minister Benjamin Netanyahu of Israel and members of his government. “At a time when you are holding holiday meals with your families, think of us, the hostages who are still here in hell, under the ground,” he says.

The Hostages Families Forum said in a statement that “the hostages must be the top priority.”

“This distressing video serves as an urgent call to take swift and decisive action to resolve this horrific humanitarian crisis and ensure the safe return of our loved ones,” the group said.

Mr. Goldberg-Polin, a dual citizen of Israel and the United States, was born in Berkeley, Calif., and was in elementary school when the family moved to Israel from Richmond, Va. He was taken captive into Gaza after part of his arm was blown off during an assault on a roadside bomb shelter.

Members of his family pieced together at least some of what happened to him through other families and survivors of the attack, and by reviewing texts and phone conversations. They have said they believed he was in desperate need of medical attention because of the injuries to his arm, which are believed to have been caused by a grenade.

In a guest essay written for The New York Times’ opinion section shortly after his abduction, his mother, Rachel Goldberg, described her son as a gentle and kind person who swam laps to raise money for a charity in Africa.

“I don’t know if he is dead or alive or if I will ever see him again,” she wrote.

His mother told reporters that her family would mark Passover this week with a Seder and “they have been very clear that if 15 minutes in we just can’t do it, and we need to cry, then we will cry.”

Mr. Goldberg-Polin ends the video by directly addressing his parents.

“I love you so much and miss you,” he told them. “It won’t be a happy holiday for me, but I wish you one.”

Malachy Browne, Johnatan Reiss and Isabel Kershner contributed reporting.