The World Food Programme, the U.N.'s worldwide food assistance program, is being "severely hampered" by the "intensifying conflict" in Gaza.

The agency said border crossings have been limited and roads in Gaza have become so unusable that urgent repairs are needed in order to transport basic needs, like food and medicine.

"Transporting food, water, medicine and hygiene equipment is critical for the survival of communities in Gaza today and will be needed for months to come," Antoine Renard, the country director for Gaza, said in a statement. "Roads are part of this lifeline."

Israeli forces issued an evacuation order in the vicinity of the Al Aqsa Hospital, Deir Al Balah, in central Gaza, urging people to flee, according to a statement from Doctors Without Borders Sunday.

"An explosion approximately 250 meters away triggered panic with many choosing to leave the hospital," the organization said.

Of the approximately 650 patients in the hospital prior to the explosion, only 100 remain, with seven in the intensive care unit, according to the Palestinian Ministry of Health.

Doctors Without Borders is considering suspending wound care for the time being, while trying to maintain lifesaving treatment, according to the statement.

"This situation is unacceptable," the organization said. "Al Aqsa has been operating well beyond capacity for weeks due to the lack of alternatives for patients. All warring parties must respect the hospital, as well as patients' access to medical care."

Sirens sounded in Tel Aviv Sunday night for the first time since January as Hamas launched a single rocket toward central Israel.

The Israel Defense Forces said the Hamas rocket fell into an "open area" in Rishon LeTsiyon, south of Tel Aviv.

Israeli emergency services officials said no one was injured by the rocket, but a 26-year-old woman was hurt going to a shelter.

Hamas confirmed it fired an "M90" rocket at Tel Aviv.

-ABC News Victoria Beaule