WASHINGTON — Samantha Power, President Obama’s choice to be the next ambassador to the United Nations, is encountering resistance from pro-Israel groups for remarks she once made about Israel and the Palestinians. But on Friday, she got an unexpected vote of confidence from Israel’s representative in the United States.

Michael B. Oren, the Israeli ambassador to Washington, said in an interview that Ms. Power, a journalist and academic who has written and spoken widely about human rights abuses, had a deep understanding of Israel’s security issues and sympathy for its concerns.

Normally, Mr. Oren said, an Israeli government official would not comment on a presidential nomination that required Senate confirmation. He said he decided to make an exception in her case to dispel an impression that the Israeli government had qualms about her.

On Wednesday, Mr. Oren posted Twitter messages welcoming the appointment of Susan E. Rice as national security adviser — a job that does not require Senate confirmation — and praising her predecessor, Tom Donilon. He remained silent on Ms. Power.