By David Brunnstrom

WASHINGTON, Feb 25 (Reuters) - U.S. President Donald Trump briefly laid out a case for a possible attack on Iran in his State of the Union speech to Congress, saying he would not allow what he called the world's biggest sponsor of terrorism to obtain a nuclear weapon.

Trump called Tehran's support for militant groups, the killings of anti-government protesters in January and the country's missile and nuclear programs threats to the region and the United States.

Here are some questions and answers about his statements:

Prince Harry and Meghan Markle arrived on Wednesday in Jordan, where they met with Syrian refugees at the Zaatari camp and Palestinian children evacuated from the Gaza Strip.

King Charles III's younger son and his wife "met young refugees... and joined children in football, art and music", the United Nations refugee agency UNHCR said in a post on X.

Jordan opened the Zaatari camp located north of Amman in 2012, a year into the war in neighbouring Syria, to host people fleeing the conflict.

Today it is home to some 45,000 refugees.

Feb 25 (Reuters) - U.S. President Donald Trump's special envoy Steve Witkoff told a private gathering on Tuesday that the administration is demanding any nuclear deal with Iran should remain in effect indefinitely, Axios reported on Wednesday, citing a U.S. official and two others with knowledge of the comments.

US Vice President JD Vance told Iran on Wednesday to take Washington's threats of military action "seriously," a day after President Donald Trump appeared to build the case for war in his State of the Union address.

As US forces mass in the Middle East, Trump claimed in his speech to Congress on Tuesday that Iran was seeking to develop missiles that can strike the United States.

German culture officials plan to summon organisers of the Berlin film festival Thursday after the event was rocked this year by controversy over the Israel-Palestinian conflict and Gaza war.

Bild daily reported that Tricia Tuttle, the US director of the Berlinale, is expected to be sacked at the meeting, citing sources close to the KBB, the state-owned company that runs the festival.

The KBB dismissed the report, telling AFP in a short statement: "We believe this is fake news."

Feb 25 (Reuters) - U.S. Vice President JD Vance said on Wednesday that President Donald Trump still preferred a diplomatic solution with Iran and that he hoped Iranians took that seriously in their negotiations on Thursday.

"The President has been as crystal clear as he could be, Iran can't have a nuclear weapon... He's going to try to accomplish it diplomatically," Vance told Fox News in an interview.

(Reporting by Bhargav Acharya in Toronto; Editing by Caitlin Webber)

SUSIYA, West Bank Feb 25 (Reuters) - Israeli settlers set fire to vehicles and tents in the Palestinian village of Susiya on Tuesday night, residents said, in the latest incidentof settler violence against Palestinians in the Israeli-occupied West Bank.

Videos verified by Reuters showed a masked group of men, who residents said were Israeli settlers, approaching the village near the city of Hebron, and later burning vehicles and Palestinian property.

An Iranian delegation headed by its top diplomat arrived in Geneva on Wednesday for talks with the US, as the Islamic republic's president struck an upbeat tone about the prospect of a negotiated agreement to avert fresh conflict.

Donald Trump has repeatedly threatened strikes if Iran fails to cut a deal on its atomic programme, and in his State of the Union address on Tuesday, the US president accused Tehran of "sinister nuclear ambitions" after he ordered a massive military deployment around the Gulf.

Feb 25 (Reuters) - The U.S. Treasury Department on Wednesday imposed new Iran-related sanctions on four individuals, several entities and tankers, according to a notice on its website.

(Reporting by Bhargav Acharya in Toronto; Editing by Daphne Psaledakis)

Egypt said Wednesday that 18 of its citizens were still missing after a migrant boat capsized, killing four people, off the Greek island of Crete last week.

The wooden boat was carrying 50 people, including four minors, when Greece's coast guard was alerted late Friday.

Greek authorities then directed a commercial vessel to the area for a rescue operation.

According to Greek public broadcaster ERT, an accident occurred when the commercial vessel approached the migrants' boat.