U.S. Secretary of State Marco Rubio said an announcement was possible later Sunday on a deal with Iran that could formally end the Middle East war, insisting goals had been met.

The United States and Iran could strike a deal to end the Middle East war as early as Sunday, Washington's top diplomat said, while Tehran insisted the agreement would do nothing to limit its nuclear program.

A gunman opened fire near the White House on Saturday evening, with U.S. Secret Service agents killing the assailant in a shoot-out during which a bystander was also struck, authorities said.

U.S. President Donald Trump said Saturday a deal with Iran had been "largely negotiated," with the proposal including opening the crucial Strait of Hormuz, though the agreement was "subject to finalization."

Tehran accused the United States of "excessive demands", Iranian media said on Saturday, as U.S. media reports raised the prospect that Washington was mulling new strikes and leaders of the Islamic republic considered the latest peace proposal.

The Trump administration was preparing Friday for a fresh round of military strikes against Iran, sources with direct knowledge of the planning told U.S. TV network CBS, even as diplomacy continued.

On the surface, Chinese leader Xi Jinping's back-to-back summits with U.S. President Donald Trump and Russia's Vladimir Putin looked pretty similar, with formal handshakes in Beijing's Tiananmen Square, enthusiastic greetings from flower-waving children, and marching columns of soldiers with gleaming bayonets. But the visits also revealed how different China's relationship is with the two countries.

During Trump's visit, China sought to stabilize ties with the United States, while Putin's trip served to deepen its strategic partnership with Russia.

The day arrived when the Senate just said, No.

President Donald Trump's political revenge tour met its potential match this week as angry, upset Republican senators, pushed to a breaking point by his seemingly insatiable and outlandish demands — particularly a $1.776 billion fund for Jan. 6 rioters and others he believes were wrongly prosecuted — did the unthinkable.

The final draft of a possible agreement between the United States and Iran, mediated by Pakistan, is expected to be announced within hours, Al-Arabiya quoted sources as saying on Friday.

Secretary of State Marco Rubio is on his latest mission to assuage nervous U.S. allies in Europe about the Trump administration's intentions with NATO or at least put a friendlier face on whipsawing changes and uncertainty about American troop reductions.

Rubio will attend a NATO foreign ministers' meeting in Sweden on Friday — the same day senior Pentagon officials are expected to brief the 32-nation alliance on plans for the U.S. military's commitment to European defense at the alliance's headquarters in Brussels.