(CNN) -- Twenty-one U.N. peacekeepers being held by rebels in Syria were taken from an area near the Golan Heights for their own safety due to fighting there, Syrian opposition coalition President Moaz al-Khatib said Thursday.
Al-Khatib told CNN's Christiane Amanpour he wants the Red Cross to pick them up.
"There was a U.N. convoy at risk" in an area under bombardment for seven days when the rebels took the peacekeepers Wednesday, al-Khatib said.
The rebels are "ready to release them on the condition that the Red Cross come and receive them from the border," al-Khatib said. Injured civilians, including women and children, should also be rescued by the Red Cross, he added.
The 21 peacekeepers are Filipino, the Philippine government said earlier Thursday.
"The apprehension and illegal detention of the Filipino peacekeepers are gross violations of international law," Philippine Foreign Affairs Secretary Albert del Rosario said in a statement.
The peacekeepers are reportedly unharmed, and negotiations are under way to secure their safe release, the Philippine government said. The Department of Foreign Affairs said it is coordinating efforts with the United Nations' peacekeeping agency.
A spokesman with the U.N. peacekeeping department said the agency was still waiting Thursday for the release of its forces. The mission has spoken with the peacekeepers over the phone and confirmed they are unharmed, the spokesman said.
U.N. spokesman Martin Nesirky told reporters Thursday that decisions on withdrawing peacekeepers from the Golan Heights rest with the U.N. Disengagement Observer Force.
"The security conditions on the ground are not easy and we have said so in recent days," Nesirky said. "It's for the commander of UNDOF to be able to assess the security situation with regard to the mission and patrols they carry out."
A video posted on the Syrian Observatory for Human Rights' YouTube website shows six of the peacekeepers sitting in a room. CNN couldn't immediately verify the authenticity of the video.
In it, one peacekeeper gives a statement to the camera:
"We are here safe in this place. We are here because while we are passing through position (unintelligible) to Jamlah, there were bombing and artillery fires. This is why we stopped and, civilian people tell us, for our safety, and distributed us in different places to keep us safe. And they give us good accommodation and give us food to eat and water to drink."
The rebels have said the peacekeepers entered a Syrian village near the Israeli-occupied Golan Heights, an area where peacekeepers should not be and where intense fighting has been raging for days between rebels and government forces.
The rebels said they suspected the peacekeepers were trying to aid their enemy -- the regime of President Bashar al-Assad.
The United Nations said the peacekeepers were on a "regular supply mission."
Two other videos that rebels posted on YouTube present the rebels' point of view.
In one, a rebel insists that the peacekeepers will be held until al-Assad's forces withdraw from the village of al-Jamlah.
The other video shows rebels walking near several U.N. trucks. "This U.N. force entered Jamlah village to assist the regime ... and (the U.N. is) claiming that they are here just to stop the clashing," a rebel says.
Members of the U.N. Security Council condemned the detention of the peacekeepers.
An Israeli official said Israel, which controls the Golan Heights, would not intervene in the situation.
"It's happening in Syria. We are following it very closely," the official said." We can't and won't interfere in the events on the other side of the border. We have offered UNDOF (the United Nations Disengagement Observer Force) any kind of assistance they might require and we hope this ends quickly with no harm to anyone."
Earlier this week, al-Khatib posted on the rebels' Facebook page a letter to U.N. Secretary-General Ban Ki-moon, the leaders of the Organization of Islamic Cooperation and the League of Arab States.
"What is happening (is a) genocide for the Syrian people with the world watching and listening (and) will lead to the gravest consequences," he wrote.
"The blood of the people of Syria will be a curse on the whole world if there" is "no effective action," it said.
There has been "hardly a Syrian village spared from the regime bombing," the letter said.
"This might be the last message to you," it warns. "I call on you all to bear your international responsibilities before God and the people."
CNN's Richard Roth and Hamdi Alkhshali contributed to this report.