Where things stand 1 month into the war with Iran

On Feb. 28, the United States and Israel launched massive strikes on Iran in an operation targeting military and government sites that President Donald Trump has said could last as little as four weeks. One month later, both countries remain engaged in a war that has impacted the wider Gulf region, killing thousands of people, as the Pentagon is preparing to surge thousands of troops to the Middle East, according to U.S. officials. As the U.S. enters its fifth week of the conflict, here's a look at how we got here, where things stand and where they may go from here. Watch special coverage on Nightline, "War with Iran," each night on ABC and streaming on Disney+ and Hulu . Operation Epic Fury began months after the U.S. and Israel carried out strikes on nuclear weapons facilities in Iran, with Trump declaring at that time that the regime's nuclear capabilities had been "obliterated." In the weeks leading up to the Feb. 28 strikes, the U.S. tried to negotiate with the Iranian regime to reach a nuclear deal, with Trump saying he was weighing whether to strike. A day before launching Operation Epic Fury against Iran, Trump said he was "not happy" with the negotiations. Ayatollah Ali Khamenei was among those killed in Tehran in the initial strikes, with his son Mojtaba Khamenei later chosen to succeed him. Trump said at the start of the "major combat operations," which occurred without Congressional approval, that they were to "defend the American people by eliminating imminent threats from the Iranian regime," and he called on the Iranian people to depose the regime. In the weeks since, more than 1,440 civilians, including at least 217 children, have died from U.S. and Israeli strikes in Iran as of March 23, according to a report from several human rights groups. Iranian officials have blamed the U.S. for a missile strike on an Iranian elementary school that killed nearly 170 people. The Trump administration has said it is investigating the incident. Iran retaliated against the strikes with missile and drone attacks targeting Israel, regional U.S. bases and multiple Gulf nations, primarily targeting U.S. interests in the region. Thirteen American servicemembers have been killed since the war began, including seven from retaliatory strikes in Kuwait and Saudi Arabia and six from an aircraft crash in Iraq. Over 300 troops have also been injured, a U.S. official said Friday. Iran has also launched a series of retaliatory strikes against the energy infrastructure in several Gulf states after Israel hit its largest gas field -- in what one Qatari official called a "dangerous escalation." Experts say the strikes and the threat of further attacks risk throwing global energy markets into a state of protracted chaos . Amid the conflict, Israel has also intensified its long-running strike campaign against the Iran-backed Hezbollah militia in Lebanon and expanded its ground operations in the south of the country. More than 1,000 people have been killed and thousands more injured in Lebanon amid this escalation, according to Lebanese officials. In response to the U.S.-Israeli strikes, Iran has effectively closed the Strait of Hormuz, a vital maritime passage for the oil and shipping trades, threatening an energy crisis. Iran has attacked several oil tankers since the war began in late February, halting nearly all shipping traffic. The supply shock has sent the price of oil surging .