Palestinians waited outside an Israeli prison in the West Bank on Sunday anticipating the release of 90 mainly female Palestinian prisoners as part of the hostage release and ceasefire deal.

As Israeli police attempted to move the crowd of mostly young Palestinian men away from the Ofer Prison, 19-year-old Ibrahim Mouadi told ABC News he is hoping to see his 27-year-old sister, Kaja Mouadi, set free. He said he hadn't seen his sister since she was arrested nine months ago when Israeli police raided their family home in the middle of the night.

Ibrahim Mouadi said he and his family have no idea why she was arrested. He said she was never charged with any offense.

“We honestly still have no clue," he told ABC News in an interview near the prison.

He said he suspects Israeli authorities detained his sister because of something she may have posted on social media.

“It’s generally because of social media posts because there is no free speech here," Ibrahim Mouadi said.

He said he and the rest of the family have only been able to communicate with his sister through written messages passed to and from her by a lawyer.

"It's been really terrible. We miss her," he said.

Now that three Israeli female hostages have been released, Ibrahim Mouadi said he is hopeful he will be reunited with his sister as soon as Sunday night.

“I’m very excited," he said.

However, he said his sense of celebration is tinged with sadness because of the suffering that has occurred in Gaza.

-ABC News' Tom Soufi Burridge, Latifeh Abdellatif, Hugo Leenhardt

As the hostage release unfolded on Sunday, horns were honking and dust was flying as trucks full of humanitarian aid passed through the Rafah border crossing with Gaza.

Now that a ceasefire has taken effect, renewed energy was seen at the critical route for getting aid into Gaza. An ABC News crew witnessed dozens of trucks carrying food, blankets and other supplies across the border gate. Several fuel tanker trucks were among those passing through the checkpoint.

Several drivers delivering the aid to a distribution point and others still waiting to do so, told ABC News they’ve been waiting at the crossing for months, with cargo neatly packed on trailers.

“Even if we can’t afford food for our families, we will put up with difficult circumstances to get it to them [the residents of Gaza],” one driver said.

Referring to the line of trucks parked outside the gates of the crossing, one driver said, “They should make it easier for trucks to get in.”

Since the war started, trucks have faced rigorous inspections by Israeli authorities.

-ABC News' Ayat Altany and Marcus Moore

The IDF confirmed that the three Israeli hostages released Sunday are meeting with their mothers at an area set up for hostages near the border with Gaza.

The hostages are also undergoing medical assessments before being taken to a hospital, according to the IDF.

-ABC News' Jordana Miller

The three female hostages who were freed on Sunday are now in Israel, the IDF and Shin Bet said in a joint statement.