UNITED NATIONS, March 23 (Xinhua) -- UN Secretary-General Antonio Guterres expressed gratitude on Friday to the 20 nations who pledged approximately 100 million U.S. dollars for Palestinian refugees to help make up a shortfall in donations from the United States.

"The secretary-general is grateful for the generous pledges of approximately 100 million U.S. dollars," said his spokesman, Stephane Dujarric, who explained the aid promises were delivered March 15 at an Extraordinary Ministerial Conference in Rome.

On Jan. 16, the UN Department of State announced that Washington was withholding aid for the UN Relief Works Agency (UNRWA) for Palestinian refugees.

"The (Rome) meeting was an exceptional demonstration of high-level support for UNRWA's mandate and a recognition for the continued necessity of its work in support of over 5.3 million Palestine refugees," Dujarric said.

"Almost 20 donors pledged additional contributions, including Qatar, Norway, Turkey, Canada, India, Switzerland and many others," he said. "The pledges made in Rome represent an important first step, yet a lot of work remains to fully close the critical shortfall."

In Washington, a U.S. State Department spokeswoman, Helen Nauert, told reporters on Jan. 16, "We committed a voluntary contribution of 60 million U.S. dollars for 2018 so far."

"Sixty million is what we have indicated as the first available tranche," she said. "That money is going to sustain schools and health services to ensure that teachers and also health care providers can be paid their salaries."

A second tranche of 65 million dollars was being withheld indefinitely, she said, adding only the United States would like to see reforms in the UNRWA operation.

However, U.S. President Donald Trump had said in a Jan. 2 tweet that the United States has contributed hundreds of millions of dollars to UNRWA without getting any signs of appreciation or respect.

"This is not aimed at punishing anyone," Nauert said. "The U.S. government and the Trump administration believe that there should be more so-called burden sharing to go around."

Dujarric, the chief UN spokesman, said: "The secretary-general encourages all member states and the private sector to provide support to UNRWA in order to close the still critical funding shortfall. He reiterates that the services provided by UNRWA to Palestine refugees are essential and contribute to bring stability to the region."