WASHINGTON — Mayor Bloomberg lavished praise on Rep. Charles Rangel as he testified before him yesterday on Capitol Hill, but he refused to weigh in on whether the Harlem congressman should step down from his position as chairman of a powerful House committee while he is under investigation.

“That’s for his committee to decide,” Mr. Bloomberg told reporters here yesterday afternoon after appearing before the House Ways and Means Committee, which Mr. Rangel heads. “I’ve known Charlie for a long time. He is a guy who understands the needs of this country. I’ve always been a fan of Charlie Rangel’s.”

Republican leaders and some newspaper editorial boards have called on Mr. Rangel to give up his chairmanship of the tax-writing panel while a House ethics committee conducts three separate inquiries into his personal finances and political activity, including his disclosure earlier this month that he had failed to report income and pay taxes on a seaside villa he owns in the Dominican Republic.

With support from the Democratic House speaker, Nancy Pelosi, Mr. Rangel has refused to step aside. A measure proposed by Minority Leader John Boehner of Ohio to strip Mr. Rangel of his committee post was voted down in the House yesterday, 226-176.

The mayor said he didn’t know anything about “the brouhaha” but noted that Mr. Rangel is “very well-respected on both sides of the aisle” in Congress. “He is genuine,” he said. “What you see is what you get with Charlie.”

Mr. Bloomberg also praised Mr. Rangel at the outset of his testimony, without mentioning the investigations that have swirled in recent weeks. “I am mayor because of Charlie Rangel,” Mr. Bloomberg said, recalling how the congressman had urged him to run for the office, but as a Democrat instead of as a Republican.

Mr. Rangel had kind words for the mayor as well, hailing him as “absolutely larger than life in our city.”