UNITED NATIONS (Reuters) - The United Nations estimates that about a quarter of Venezuelans are in need of humanitarian assistance, according to an internal U.N. report seen by Reuters on Thursday that paints a dire picture of millions of people lacking food and basic services.

FILE PHOTO: Maria Guitia washes her son Yeibe Medina at home near San Francisco de Yare, Venezuela, February 18, 2019. REUTERS/Carlos Garcia Rawlins/File Photo

The report’s findings contrast with comments from President Nicolas Maduro, who has said there is no crisis and no need for humanitarian aid, blaming U.S. sanctions for the country’s economic problems.

The United Nations has found itself stuck in the middle of the political struggle that pits Maduro against U.S.-backed opposition leader Juan Guaido, who invoked the constitution to assume an interim presidency in January, arguing that Maduro’s 2018 re-election was illegitimate.

Last month, Venezuelan government troops blocked U.S.-backed aid convoys entering from Colombia and Brazil.

However, Maduro’s government has accepted aid from ally Russia.

“The politicization of humanitarian assistance in the context of the crisis makes delivery of assistance in accordance with the principles of neutrality, impartiality and independence more difficult,” reads the 45-page U.N. “Overview of Priority Humanitarian Needs” in Venezuela.

Venezuela’s information ministry did not immediately respond to a request for comment.

The March 2019 U.N. review uses a “broad range” of sources - including U.N. agencies, the Red Cross, academia and civil society - and is part of a push by the world body to try and scale up its humanitarian response in Venezuela.

“Much more action is required to meet the growing needs of the Venezuelan people,” reads the report, which warned that a lack of reliable, official data made it difficult to accurately determine the scope of need.

It estimates 94 percent of the 28.8 million people live in poverty, while some 3.4 million people have fled, with a further 1.9 million expected to follow in this year.

“Due to an increasingly contracted economy and political unrest, the Venezuelan population is facing unprecedented challenges in accessing essential services, including protection, healthcare, medicines, vaccinations, water, electricity, education and access to food,” the report said.

There are an estimated 2.8 million people in need when it comes to healthcare, according to the U.N. review, including some 300,000 people whose lives are at risk because they have been unable to access medicines or treatment for diseases like cancer, diabetes and HIV for more than a year.

“Preventable diseases such as tuberculosis, diphtheria, measles and malaria have resurfaced in the country and are on the rise, as is hepatitis A, due to the lack of access to safe drinking water,” the report said.

In the area of water, sanitation and hygiene, 4.3 million people are in need of help, according to the report.

It said a shortage of food had left some 1.9 million people in nutrition need, while an increase in violence in the country meant some 2.7 million Venezuelans were vulnerable.

Some 1.2 million children are not in school due to the crisis, the report said, because many families cannot afford the clothing, footwear or transportation required and children are instead working to help pay for their family’s essential needs. Another 1 million were found to be highly vulnerable to dropping out of school.