JOHN YANG: Good evening, I'm John Yang.

There are new fears tonight of a wider Middle East conflict after at least 10 children and young adults were killed in our rocket attack on a soccer field in the Israeli controlled Golan Heights.

Israel said Hezbollah militants were responsible, but the group said it struck a military base in retaliation for Israeli attacks on a village in Lebanon.

In Gaza, an airstrike hit a school in what had been designated a humanitarian zone.

Israeli military said Hamas use the area to store weapons and plant attacks.

Gaza health official said more than 30 people were killed.

Wildfires are devastating communities in the western United States and Canada.

In California, the park fire north of Sacramento covers 480 square miles that's about the size of Los Angeles.

Hot windy conditions are pushing it north.

Four counties are under evacuation orders and more than 130 structures have been destroyed.

And in Canada, a fast moving fire has devastated the resort town of Jasper, Alberta and the Canadian Rockies.

It's forced the evacuation of 25,000 people in and around Jasper National Park, which is a World Heritage Site.

Vice President Kamala Harris's campaign said today that America's democracy is under assault by former President Donald Trump.

It was in response to a speech Trump made to Christian conservatives Friday night.

He said that if they elect him in November, they would never have to vote again.

DONALD TRUMP, Former U.S. President: Christians get out and vote just this time.

You won't have to do it anymore.

Four more years.

You know what?

It'll be fixed.

It'll be fine.

JOHN YANG: Late yesterday, the FBI moved to end speculation about this month's assassination attempt on Trump.

They said that a bullet not shrapnel hit him at that rally in Pennsylvania.

At the Olympics there are fresh concerns about whether the river sand will be clean enough for competition next week, played a big part in yesterday's opening ceremony.

But the runoff of wastewater from heavy rain has renewed worries about high bacterial levels.

The river has to be the venue Tuesday for the swimming leg of the men's triathlon.

And Team USA picked up its first gold medal today in the men's 4 by 100 freestyle swimming relay.

The first gold medal overall went to China and the 10 meter air rifle mix team competition.

Still to come on PBS News Weekend, how new technology helps retailers keep the prices shoppers pay in flux, and the art and sport of breaking as it makes its Olympic debut.