The short video clip shows Mia Schem lying on a bed, her right arm being bandaged by someone out of the frame. A long, fresh scar is clearly visible.

Schem, a 21-year-old French-Israeli woman, is being held hostage by the militant group Hamas in the Gaza Strip. The video released by Hamas on Monday is the first footage of any of the dozens of people held in the enclave.

Speaking into the camera, Schem, who looks pale, but is sitting up straight with her head held high, says she was injured and taken to Gaza, then pleads to be returned to her family.

As she speaks, loud rumbling can be heard in the background.

Speaking to reporters on Tuesday in Tel Aviv, Schem's mother urged the government and world leaders to bring her daughter back home.

Holding a picture of her daughter, Keren Scharf Schem said: "I am begging the world to bring my baby back home, she only went to a festival party to have some fun and now she is in Gaza and she is not the only one."

Scharf Schem said she did not know if her daughter was dead or alive until Monday and that all she knew is that she might have been kidnapped.

"I saw she is alive, I saw that she was... I heard before rumors that she was shot in the shoulder or in the leg so I can see she was shot in her shoulder, I see she had an operation, she looks very terrified, she looks like she is in big pain, and I can see that she says what they tell her to say," she told reporters, urging everyone to "stop this terror" and bring her daughter back home along with other hostages.

Schem's mother told CNN on Monday that she believed her daughter's resilience would help her survive. "She's very, very strong. That's why we all believed in our hearts that she is alive, because we knew that she will never give up."

CNN cannot independently verify where and when the video of Schem was taken and what condition she is in at the moment.

The Israel Defense Forces (IDF) said in a statement that it had informed Schem's family about her kidnapping last week and are keeping in touch with them at this time.

IDF spokesperson Maj. Libby Weiss told CNN on Tuesday that the release of the video was "another way by Hamas to wage a psychological war" on civilian population of Israel. CNN is not publishing the video.

'We're waiting for you, we love you'

It is still unclear how many hostages are held in Gaza. A spokesperson for Hamas' military wing, the Al-Qassam Brigades, said in a video statement on Monday the number was at least between 200-250.

The spokesperson, Abu Obaida, said the Al-Qassam Brigades held about 200 hostages, while the rest was held by other "militant formations" in Gaza, adding that they cannot determine the exact number of hostages in the strip at this stage due to constant Israeli bombardment.

The IDF has been relentlessly pounding Gaza with airstrikes and artillery following the deadly Hamas terror attack. Palestinian news agency WAFA reported on Monday that more than 2,800 people have been killed in Gaza.

Earlier on Monday, the Israeli military said at least 199 people were being held hostage in Gaza. The IDF said it was using "all intelligence and operational means to return the abductees" and that "Hamas is trying to present itself as a humanitarian organization while acting as a hideous terrorist organization responsible for killing and kidnapping infants, women, children and the elderly."

Meanwhile, Abu Obaida claimed 22 of the hostages in Gaza were killed in Israeli airstrikes, including an Israeli artist whom he said lost his life on Saturday. CNN cannot independently verify those claims.

Abu Obaida added that the Al-Qassam Brigades will be releasing hostages holding foreign citizenship when "the opportunity arises on the ground," and said Al-Qassam is "committed" to protecting them.

Schem was kidnapped from the Nova festival near the Gaza Strip after Hamas fighters launched a terror attack last Saturday that so far killed at least 1,400 people.

At least 260 people were found dead is the site of the festival, according to the IDF.

Scharf Schem said her daughter had messaged a friend who was also at the festival at 7:17 a.m. on Saturday morning saying, "They are shooting at us please come save us."

Calling her daughter the "heart of the family" Scharf Schem described Mia as a caring sibling and "her best friend."

"Mia if you can see us, we want to tell you from all the family and all the people in Israel," Schem's brother Eli Schem told CNN. "We're waiting for you, we love you, and we are going to do anything to bring you back home."