The United States and Britain have struck Iran-backed armed groups in Syria, Iraq and Yemen, while Israel presses ahead with its offensive against Hamas in Gaza. Here is what to know about what is happening in the region now, and why:

US ATTACKS ON GROUPS BACKED BY IRAN

Israel's military has issued its most detailed warning yet to Hezbollah that it would be "ready to attack immediately" if provoked, as it recounted its actions along the Lebanese border during four months of war in Gaza and made a rare acknowledgement of dozens of airstrikes inside Syria against the Lebanese group.

"We do not choose war as our first priority, but we are certainly prepared," military spokesperson Daniel Hagari said, adding: "We will continue to act wherever Hezbollah is present, we will continue to act wherever it is required in the Middle East. What is true for Lebanon is true for Syria, and is true for other more distant places."

A man injured three people Saturday in a stabbing attack at the major Gare de Lyon train station in Paris, another nerve-rattling security incident in the Olympic host city before the Summer Games open in six months.

Paris police said officers quickly detained the attacker who used a sharp weapon in the assault at around 8 a.m. One of the people injured was in a serious condition; the other two were more lightly hurt.

The U.S. military overnight launched an air assault on dozens of sites in Iraq and Syria used by Iranian-backed militias and the Iranian Revolutionary Guard, in the opening salvo of retaliation for the drone strike that killed three U.S. troops in Jordan last weekend.

The massive barrage of strikes hit more than 85 targets at seven locations, including command and control headquarters, intelligence centers, rockets and missiles, drone and ammunition storage sites and other facilities that were connected to the militias or the IRGC's Quds Force, the Guard's expeditionary unit that handles Tehran's relationship with and arming of regional militias. And President Joe Biden made it clear in a statement that there will be more to come.

Hamas officials said that the group is studying a proposed cease-fire deal that would include prolonged pauses in fighting in Gaza and swaps of Israeli hostages for Palestinian prisoners, but the militants appeared to rule out some key components.

Hamas remains committed to its initial demands for a permanent cease-fire, the group's top political leader Ismail Haniyeh and a senior Beirut-based official, Osama Hamdan, said. Hamdan also said the group seeks the release of thousands of Palestinian prisoners being held for acts related to the conflict with Israel, including those serving life sentences.

The U.S. military launched an air assault on dozens of sites in Iraq and Syria used by Iranian-backed militias Friday, in the opening salvo of retaliation for the drone strike that killed three U.S. troops in Jordan last weekend, officials told The Associated Press.

President Joe Biden and other top U.S. leaders have been warning for days that the U.S. would strike back at the militias, and they made it clear that it wouldn't be just one hit, but would be a "tiered response" over time. The officials spoke on condition of anonymity to discuss military operations not yet made public.

When Mark Zuckerberg turned at a Senate hearing to address the parents of children exploited, bullied or driven to self harm via social media, it felt like a time-worn convention had sprung back to life.

"I'm sorry for everything you've been through," the Meta CEO said Wednesday. "No one should go through what you and your families have suffered." Then he returned to corporate mode, noting Meta's continued investments in "industrywide" efforts to protect children.

Norwegian authorities issued several warnings for landslides and avalanches in southern Norway Friday as bad weather continued to hammer the Scandinavian country. In the northern part of the country, officials said roads might be closed at short notice.

Flights to and from the airport in Tromsoe, a city in the Arctic, resumed Friday after some 200 passengers had to sleep there because of Norway's most powerful storm since 1992.

Climate activist Greta Thunberg spoke defiantly about her mission outside court Thursday on the first day of her trial for refusing to leave a protest that blocked the entrance to a major oil and gas industry conference in London last year.

Thunberg, 21, was among more than two dozen protesters arrested on Oct. 17 after preventing access to a hotel during the Energy Intelligence Forum, attended by some of the industry's top executives.

Local buses, trams and subway trains were canceled in much of Germany on Friday as transport employees walked off the job in the country's third transport-related strike in two weeks.

The Ver.di service workers' union called for a "warning strike," a common tactic in German contract negotiations, on Monday. Its deputy chair, Christine Behle, said that "the time has now come to exert more pressure on employers" as talks on new pay contracts for about 90,000 people employed by over 130 local transport operators have failed to make progress.