Further US, Iran flare-up hanging in the balance

United States President Donald Trump warned on Saturday that Washington would hit dozens of Iranian targets "very fast and very hard" if Teheran retaliates for the US targeted killing of its top general, and a former national security adviser cautioned that the US is not safer after the attack.

A day after announcing that "the United States military successfully executed a flawless precision strike" on Iranian military commander Qassem Soleimani and an Iraqi militia leader, Trump ramped up his rhetoric against possible reprisals from Iran, which has vowed to punish US citizens "wherever they are in reach".

In a series of tweets posted on Saturday, Trump wrote Iran "is talking very boldly about targeting certain USA assets" in revenge for Soleimani's death. He wrote that in the event of any Iranian reprisals, the US had "targeted 52 Iranian sites" and that some were "at a very high level & important to Iran & the Iranian culture, and those targets, and Iran itself, WILL BE HIT VERY FAST AND VERY HARD."

For Iran, Soleimani's killing was a "horrific assassination", Iranian Ambassador to the United Nations Majid Takht Ravanchi said in a letter to UN Secretary-General Antonio Guterres. It is "an obvious example of state terrorism, and, as a criminal act, constitutes a gross violation of the fundamental principles of international law," Ravanchi wrote.

Susan E. Rice, the US national security adviser from 2013 to 2017, said an Iranian response would likely be multifaceted and occur at unpredictable times and in multiple places.

"President Trump will then face what may yet be the most consequential national security decision of his presidency," she wrote in an op-ed piece in The New York Times on Saturday.

If he reacts with additional force, the risk is great that the confrontation will "spiral into a wider military conflict". If he fails to react in kind, he will likely invite escalating Iranian aggression, Rice wrote.

"One thing is clear: Americans are not safer, as Secretary of State Mike Pompeo argued on Fox News the morning after. Rather, American citizens are at greater risk of attack across a far wider battlefield than before," she wrote.

Hundreds of US soldiers were deployed on Saturday from Fort Bragg, North Carolina, to Kuwait to serve as reinforcements in the Middle East amid rising tensions following the killing of Soleimani, the Associated Press reported.

The US has failed to deter Teheran thus far, even with the deployment of 14,000 additional American troops to the Gulf region since May, Rice noted.

"The announcement this week that the Pentagon was sending 3,500 more soldiers from the 82nd Airborne Division seems unlikely to change things," she wrote.

Jon B. Alterman, a senior vice-president of the Center for Strategic & International Studies in Washington, said that after the drone attack on the Iranian military leader, Iran will respond, forcing itself to the forefront of US foreign policy considerations for years to come and drawing Washington into precisely the sort of shadowy battles the Pentagon has been trying to avoid for more than a decade.

"As a consequence of this action, the United States will grow more enmeshed militarily in the Middle East despite President Trump's avowed desire to leave the region," Alterman, who is also director of the Middle East Program at the center, said in a post on Friday.

On Saturday, hundreds of demonstrators chanted outside the White House "No justice, no peace. US out of the Middle East". Later, they marched to the Trump International Hotel a few blocks away. Similar protests were held in New York, Chicago and other cities, according to Reuters.

The international community has urged all related parties to exercise "maximum restraint" to avoid further escalating Middle East tensions. Some experts said there is still opportunity for Washington and Teheran to step back instead of further escalating the tensions.

Michele Dunne, director and senior fellow of Middle East Program at the Carnegie Endowment for International Peace, said the small window of opportunity for diplomacy to avert a disastrous conflict is within the next few days.

"It is in both US and Iranian interests to preserve the option of diplomacy to resolve the outstanding issues (Iran's regional interventions and nuclear program, US sanctions) before tragedy ensues," Dunne, a US State Department Middle East specialist from 1986 to 2003, said in an article posted at Carnegie Endowment's website.