Nancy Pelosi said Iran was a concern to both the US and Israel
Israeli Prime Minister Benjamin Netanyahu has said he sees US Congress as "great friends of Israel" as he seeks support from US leaders.
Mr Netanyahu met House Speaker Nancy Pelosi and House Minority Leader John Boehner on a visit to Capitol Hill.
They said they shared Israel's concern over Iran's nuclear plans and pledged help finding peace in the Middle East.
Secretary of State Hillary Clinton said she had stressed US calls for a freeze on settlement building to Mr Netanyahu.
On Monday, President Barack Obama urged the visiting prime minister to accept a Palestinian state.
Mr Obama restated his support for a two-state plan and said the US would be "engaged in the process".
He also said Israel had an obligation under the 2003 "roadmap to peace" to stop Jewish settlement in the West Bank.
In Tuesday's meetings on Capitol Hill, the Israeli prime minister met members of the Senate Foreign Relations Committee and then headed for talks with House and Senate leaders and a group of Jewish legislators.
Committee chairman Senator John Kerry said he was "encouraged by a number of things" Mr Netanyahu said, but did not go into detail.
Senator Kerry said he had also stressed to Mr Netanyahu "the importance of Israel moving forward, especially in respect to the settlements issue".
Mr Netanyahu told Democrat Ms Pelosi and Republican Mr Boehner that he saw "an American consensus" regarding "the special relationship we have between Israel and the United States".
"We face opportunities and [a] challenge. The challenge is the potential arming of Iran with nuclear weapons capabilities. That is a great danger to all of us," he warned.
Mr Netanyahu said he would pursue "the advancement of peace between us and the Palestinians" as well as normal relations with the wider Arab world.
"We have to do this in tandem," he said. "I was very encouraged to learn that this is the American policy. We're going to try to do it together, because if we do it together we'll get a lot further, a lot faster."
Ms Pelosi said the question of Iran was "one that is of concern to us in Congress".
"It is an issue for the world," she said. "It is important for all of us to work together to be sure that Iran does not develop a weapon of mass destruction."
At a news conference, Secretary of State Hillary Clinton said she had hosted a dinner for Mr Netanyahu on Monday and had reiterated that Mr Obama "wants to see a stop to the settlements".
Mr Netanyahu also held an hour-long working lunch with Defence Secretary Robert Gates, who told him there would be "much stronger international sanctions" if Iran rebuffed US diplomatic overtures.
Earlier, Israeli Defence Minister Ehud Barak said he was optimistic after Monday's talks between Mr Netanyahu and President Obama.
"I spoke with Netanyahu last night. I think that this is the beginning of a serious dialogue with the Americans," he said.