Pressure is building on the Serbian government after reports that it used an illegal sonic weapon on protesters in Belgrade.

Authorities denied the claims but video footage of the incident has intensified "mounting speculation" about the dispersal tactics used by security forces. Half a million people have signed a petition demanding an independent investigation. 

What happened at the protest?
Tens of thousands were holding a peaceful anti-corruption rally on 15 March when "we heard something we could not see, like a sound rolling towards us", said protester Ivana Ilic Sunderic. It was "very unusual and very frightening, like a sound from hell", she told Sky News.

The video, taken by The Associated Press, appears to show thousands of protesters "suddenly start running away in panic". A "swooshing sound" can be heard. Campaigners say this is the moment when the protesters were "targeted" with a "sound cannon".

Sonic weapons, illegal in Serbia, send out sound waves which can cause pain, disorientation, eardrum rupture and even permanent hearing damage. Protesters said they have been suffering from "lingering headaches, nausea and ringing in the ears" since the rally, said The Guardian.

What do authorities say?
Serbian President Aleksandar Vucic said it was "wicked lie" that a sonic weapon had been used, but a photo taken at the rally appears to show "a police vehicle with a large piece of equipment fixed to the bonnet", said The Guardian.

When shown the photo, officials admitted possessing a sonic weapon but "insisted it was not used", said The Independent. Interior Minister Ivica Dacic said the vehicle housed nothing more than "loudspeakers" that "serve to emit warnings to the crowds".

What do experts say?
The photo shows "what appears to be a LRAD 450XL" sonic weapon, said The Independent, although Genasys, the US manufacturer, said neither the photo nor the video prove that an LRAD was used.

But Predrag Petrovic, from the Belgrade Center for Security Policy, said there was a "huge probability" that "some version of a sonic cannon" was used. "I have never seen a stampede happen in a second, and along an almost straight line," he told the paper.

What might happen next?
The petition, organised by the Serbian opposition Move-Change movement, demands an investigation by the United Nations and the Council of Europe. Several rights organisations have also "taken the issue to the European Court of Human Rights", said AP. Serbia has until the end of the month to respond.

Ten years ago, Xi Jinping launched a multibillion-dollar crusade to fulfil his three wishes: for China to qualify for the football World Cup; host it, and win it.

But the president's ambitions seem further away than ever. China's miserable World Cup qualifying campaign has led to calls for the men's football team to be disbanded, and angry questions about why a country of 1.4 billion people can't find 11 players capable of winning a match.

'Football-mad man of the people'
In 2015, Xi said he wanted China's men's team to become "one of the best in the world". The government launched a project to make the country a "football superpower" by 2050.

The plan was "closely linked to the burgeoning cult" around Xi, presented in state media as a "football-mad man of the people", seen "kicking balls around", said Ian Williams in The Spectator.

Then, China were 81st in the Fifa world rankings. Now, they are 90th. The lowest point came last September when China were thrashed 7-0 by Japan – close to a record defeat. The state-controlled Global Times called China's performance "shameful". This week, Australia beat China 2-0 in Hangzhou, confirming China's place at the bottom of their World Cup qualifying group.

Creativity not perfection
The reasons for this continued failure "tell you a lot about how the country is run", Rowan Simons, author of "Bamboo Goalposts: One Man's Quest to Teach the People's Republic of China to Love Football", told the BBC.

State interference in the way football authorities run is against Fifa's rules, but China's one-party state imposes decisions from the top, and Chinese football is dominated by political appointments. Its top football body is also plagued by "rampant corruption", match-fixing and bribery, wrote Edi Obiakpani-Reid on Sinobabble.

And Chinese children are "educated and socialised" differently from European kids: they're taught "there is always a right and a wrong answer", David Sproer, who worked as youth coach in the country, told the BBC. But "you have to be a little bit more versatile in football" than in the other sports where China does well, such as diving. "It's not about perfection; it's also about creativity."

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The unpredictability of Trump's tariffs will increase the pain
The Economist's editorial board
"Just as damaging" as Donald Trump's tariffs, says The Economist, has been "the uncertainty about what comes next". Will his "plans change"? His "use of emergency powers" means that "he can do as he pleases". America needs "liberation from the paralysing uncertainty" caused by his "chaotic approach". And other countries could "bring down barriers" and integrate with each other "as Trump pulls America back".

Why I'm a pro-screen parent
Arabella Byrne in The Spectator
"Have you ever looked after a child for the standard 14-hour shift and not turned a screen on?" writes Arabella Byrne. And "don't lie, because no mother on this planet will believe you". We know that the "only way" to make it through the "never-ending day" is to fill it with "chunks" of screen time. So "fellow mothers, I implore you" not to "feel bad" – just "press play and enjoy".

I've seen King Charles hard at work – one aspect of setback doesn't surprise me
Russell Myers in The Mirror
The King's decision to cancel "a raft of engagements" is "not one he would have taken lightly", writes Russell Myers. His return to "public duties" despite his "cancer battle" is a "testament to his desire to do the job the way he sees it should be done". The Palace describes his latest "setback" as "a bump in the road", so "let's hope the King finds himself back on track" soon.