Here's the biggest news you missed this weekend

Trump tweets in support of Iran protests; Iranian general apologizes for passenger jet tragedy

Iranian leaders said late Friday that their country's missiles unintentionally shot down a Ukrainian jet that crashed after taking off from Tehran this week. And the fallout from U.S.-Iran tensions intensified Sunday as missiles pounded an Iraqi air base hosting U.S. troops. At the same time, Iranians defied a government crackdown and protested their government's accidental shootdown of the passenger jet. President Donald Trump tweeted his support for the demonstrations, warning there "cannot be another massacre of peaceful protesters." Here is what we know so far:

• Four Iraqi soldiers were wounded Sunday when at least six rockets slammed into the Balad air base 50 miles north of Baghdad, the Iraqi military said. There was no immediate word of U.S. casualties. The statement made no mention of Iran, and no group or nation immediately took responsibility for the attack.
• The Iranian military promised to deal with the plane strike in military court. “I swear to almighty God that I wished I was on that plane and had crashed with them and burned but had not witnessed this tragic incident,” Gen. Hossein Salami, head of Iran's Revolutionary Guard, said Sunday. “I have never been this embarrassed in my entire life. Never.”
• Protesters have taken to the streets in Iran, shouting slogans and demanding the leaders be held accountable. Iranian President Hassan Rouhani issued a statement assuring that those who are responsible for the tragedy will be prosecuted.
• Defense Secretary Mark Esper said Sunday he had not seen specific evidence that Iran planned an imminent attack on four U.S. embassies, as Trump has asserted, but said he and several members of the administration's national security team shared the president's view that the embassies were potential targets. 
• And did Iran mean to kill Americans in its Iraq attack? The answer hints at how far Iran will go to challenge the U.S.

At least 11 dead as tornadoes, heavy rain and wicked winds lash southern US, Midwest

A two-day pounding of severe weather across portions of the southern U.S. and into the Midwest left 11 people dead, prompting two governors to declare states of emergency as tornadoes, heavy rainfall and high winds ravaged the region. Two first responders in Lubbock, Texas, were among the fatalities, killed when they were hit by a vehicle at the scene of a traffic accident in icy conditions. In Oklahoma, a man drowned after being swept away from his stalled truck by floodwaters. And in Alabama, a tornado with winds up to 134 mph descended on Pickens County and killed three.

• Two first responders killed and another injured at icy wreck scene in Texas.

Real quick

• Serena Williams ends three-year title drought, donates $43K winner's check to Australian wildfires victims.
• After Prince Harry and Duchess Meghan's historic announcement about "stepping back" from their royal duties, the family will meet Monday to discuss next steps.
• Twelve Saudis reportedly to be expelled from US after Pensacola shooting rampage that killed three American service members.
• New England Patriots wide receiver Julian Edelman arrested for alleged vandalism in Beverly Hills.
• Samsung introduces Galaxy XCover Pro, a durable, enterprise-ready smartphone with a removable battery.
• Magnitude 5.9 earthquake rocks Puerto Rico and causes landslide in the southern municipality of Peñuelas.

Pelosi warns Senate Republicans will 'pay a price' if they engage in a 'cover-up'

As House Speaker Nancy Pelosi prepares to send the two articles of impeachment against President Donald Trump to the Senate, she warned Majority Leader Mitch McConnell that an attempt to dismiss the case without a trial would be perceived as a "cover-up." Last month, the House impeached Trump on charges of abuse of power and obstruction of Congress. On Thursday, McConnell signed onto a resolution to dismiss the articles for "failure to prosecute" if they were not sent to the Senate within 25 days of their adoption by the House, which took place Dec. 18. 

Volcano erupts near Manila; tens of thousands evacuate, international airport shuts down

A small volcano near the Philippine capital erupted with a massive plume of ash and steam Sunday, prompting the evacuation of tens of thousands of people and forcing Manila’s international airport to shut down. The Philippine Institute of Volcanology and Seismology said Taal Volcano blasted steam, ash and pebbles 6 to 9 miles into the sky— a dramatic escalation of its growing restiveness. The volcanology institute raised the danger level around Taal three notches on Sunday to level 4, indicating “a hazardous eruption may happen within hours or days,” said Renato Solidum, who heads the institute.

NFL conference championship matchups are set

Divisional playoff wins by the Kansas City Chiefs and Green Bay Packers on Sunday set up next week's conference championship matchups. While the Chiefs will host the Tennessee Titans -- who pulled off the biggest stunner of the weekend knocking off the Baltimore Ravens -- the San Francisco 49ers will host the Green Bay Packers. 

• Chiefs' wacky playoff win had to be seen to be believed: Patrick Mahomes threw for touchdowns on seven consecutive possessions as Kansas City won a wild one.
• Two Aarons, two Smiths help Packers advance: Aaron Jones, Aaron Rodgers, Preston Smith and Za'Darius Smith played vital roles in putting Green Bay in the NFC title game.
• Ravens' dream season crumbles in astonishing fashion: The top-seeded Ravens seemed to have the making of a Super Bowl contender. Then their stunning run came to an abrupt end.
• Richard Sherman hits back on critics after 49ers' win: 'I get tired of hearing the excuses for why I’m great.'
• Titans RB Derrick Henry on what he told Earl Thomas after stiff-arm: 'Good to see you.'

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Contributing: Associated Press.