The United Nations appealed on Monday for $54 million to help meet the growing needs of tens of thousands of Syrian refugees in Jordan, particularly children who "suffer most."
The UN Children's Fund UNICEF said in a statement the funds are "urgently" needed "to meet the emergency health, protection, and water and sanitation needs of the growing numbers of Syrian refugee children and their families arriving in Jordan."
Jordan is hosting around 200,000 Syrian refugees -- 17,000 are sheltered at the UN-run Zaatari refugee camp in the north and half of them are children.
"We expect to have 70,000 people at Zaatari camp by the end of this year," said the UNICEF's Jordan representative Dominique Hyde.
"We must act now because it is children who continue to suffer most. So more funding is urgently required to scale-up our emergency response activities."
UNICEF said conditions at the seven-square-kilometre (two-square-mile) Zaatari camp are "harsh, with scorching temperatures, no natural shade, and frequent sandstorms that rip through the camp."
"There was a significant increase in the number of arrivals at the camp this last weekend with more than 2,000 people crossing the border in a single night," it said.
"This number is nearly 80 percent higher than the previous largest number of Syrians crossing into Jordan within a 24-hour period."
The UN warned that "as the number of children increases, so does the risk of disease outbreaks."
"This week, UNICEF is partnering with the Ministry of Health and the World Health Organisation to immunise children under five, many of whom will have missed routine vaccinations due to the violence in Syria."
"UNICEF is working with partners to establish a regular vaccination programme at the camp," it said.
Hyde said children fleeing violence in Syria are at risk of suffering long-term distress without appropriate care."
"In just a few months, we expect as many as 35,000 children will be at the camp, so we urgently need to provide additional safe places and other support to protect these children who have already suffered so much," he said.