From Washington, this is VOA news. I'm Joe Parker reporting. At the Democratic convention, Bernie Sanders is booed by his own delegates.

"I hereby call the 47th quadrennial Democratic National Convention to order!"

Stephanie Rawlings-Blake, mayor of the eastern city of Baltimore who is also secretary of the Democratic National Committee, opened the convention tonight in place of Debbie Wasserman Schultz, the DNC chair.

Wasserman Schultz was pushed out of that post on Sunday in the aftermath of the WikiLeaks disclosure of nearly 20,000 emails.

The U.S. Democratic Party has opened its four-day national convention in the eastern city of Philadelphia, trying to put on a show of unity in the face of controversy over leaked emails that show party leaders sought to ease [Hillary's] Hillary Clinton's path to the nomination.

Before the convention formally began, Sanders called on his supporters to get behind Hillary Clinton, pressing for united front against Republican Donald Trump.

"We have got to elect Hillary Clinton and Tim Kaine."

But the boos and the angry chants when he called for her election seemed to tell a very interesting story that will play out this weekend in Philadelphia.

Officials in Japan now say 15 people were killed in a knife attack on Tuesday at a center for disabled people west of Tokyo. Dozens more were injured.

Japan's national broadcaster, NHK, says police arrested in a knife-wielding man after he turned himself in. NHK described the 26-year-old suspect as a former employee at the facility.

The motive for the attack is not clear. However, a newspaper reported that police quoted the suspect as saying "I want to get rid of the disabled from this world."

This is VOA news.

At least three people have been detained after a shooting at a nightclub in the southeastern U.S. state of Florida that left two people dead.

The motive for the shooting is not clear, but police said in a statement this incident was not an act of terror.

Officials say at least 17 people were wounded in the incident early Monday outside of the Fort Myers nightclub, which was holding an event for teenagers.

Jean Archilles, whose son Sean was one of the two people killed in the shooting, was asked about his young son.

"My best memory, because he always wanted to hang with me and he always wanted to spend time with me, always calling me on the phone."

Hospital officials say at least two of the injured are in critical condition. The victims ranged in age from 12 to 27 years old.

U.S.-backed Syrian forces are closing in on Islamic State militants inside the town of Manbij in Syria's northern province of Aleppo.

Fighters from the Manbij Military Council, which is allied with the anti-IS Syrian Democratic Forces, said that they are now in control of the majority of the city and their operation to liberate the town will be completed soon.

According to local fighters, nearly 80 percent of the city has been cleared of IS militants.

In a move seen as intended to ease political tensions, Turkey's president met with the political opposition today.

But Dorian Jones reports from Istanbul concerns continue to grow that a crackdown on plotters of the failed coup earlier this month is extending to critics of the president.

Soli Ozel, an international relations expert at Istanbul's Kadir Has University, says the symbolism of Monday's meeting is an important step toward easing tensions.

"Mr. Erdogan is usually seen as a polarizing figure, so when he takes conciliatory steps, this resonates far more than anybody else's steps."

But tensions remain high amid fears the ongoing crackdown is extending beyond those involved in the coup. Turkey is currently under emergency rule, and more than 60,000 people have been arrested or suspended from work.

Human rights group Amnesty International alleges some of those detained have been ill-treated and tortured.

Dorian Jones, for VOA news, Istanbul.

Observers warn that as the scope of arrests appear to be broadening, time could be running out for building a cross-party consensus, threatening further turmoil.

Members of the SPLM In Opposition nominated Taban Deng Gai over the weekend (to) become South Sudan's acting first vice president to replace Riek Machar, who went into hiding shortly after fighting broke out in the capital of Juba in early July.

Machar's spokesman, Peter Gadet, condemned the nomination.

Joe Parker reporting from Washington.

That's the latest world news from VOA.