From Washington, this is VOA news. I'm Jonathan Jones reporting.

Turkish President Recep Tayyip Erdoğan vowed Monday to expand Turkey's military operations against more Kurdish strongholds in Syria after ousting Kurds from their enclave in Afrin.

Erdoğan said Turkish forces would target the Syrian city of Manbij, along with Ayn al-Arab, also known as Kobani, and other towns along the Turkish-Syrian border to the east of the Euphrates River.

American troops, however, are stationed in Manbij as part of the effort to eradicate the Islamic State terrorist group.

Turkish authorities have detained four men after they were found to have large quantities of a radioactive nuclear element in their car.

The element is known as Californium. It was found when a car was searched in the Ankara suburb of Pursaklar on Monday during an anti-smuggling operation.

Police said the four were part of a criminal gang that was planning to sell the rare material on the black market for more than $70 million.

The seized material was taken to the Turkish Atomic Energy Authority for further examination.

Californium is believed to be produced only in the U.S. and Russia.

A Syrian government minister on Monday said some rebels in eastern Ghouta may soon agree to [withdrawn] withdraw from the opposition enclave or accept rule by the Syrian state.

And South Korean prosecutors say they've requested an arrest warrant for former President Lee Myung-bak over corruption allegations.

He is just the latest South Korean leader to be entangled in scandals or other problems after leaving office.

Lee denies any wrongdoing.

This is VOA news.

Major U.S. and European stock indexes were sharply lower in Monday's trading over continuing fears of a trade war, Brexit, an upcoming U.S. Federal Reserve meeting and trouble with Facebook.

The price of Facebook shares plummeted 7 percent on Monday.

The U.N. aid chief, Mark Lowcock, says humanitarian needs have doubled in Congo over the last year as a result of conflict.

"Thirteen million people need humanitarian assistance. More than 4.6 million children are acutely malnourished, including 2.2 million suffering severe acute malnutrition."

Lowcock told the U.N. Security Council on Monday that Congo is also experiencing "mushrooming epidemics, including the worst outbreak of cholera in 15 years."

European Union foreign ministers took on some hot-button issues Monday, throwing their weight behind Britain, which claims Russia is likely behind a poisoning attack on a former spy.

They also talked about sanctions against Iran and North Korea.

Correspondent Lisa Bryant has more from Paris.

European foreign ministers in a statement offered full backing to Britain's claim it was highly likely Russia was behind the deadly nerve agent attack against former Russian spy Sergei Skripal and his daughter.

Skeptics previously suggested Europe might not be so united, but British Foreign Minister Boris Johnson suggested Moscow's alleged effort to ???shield visions has failed.

"There is scarcely a country round the table here in Brussels that has not been affected in recent years by some kind of malign or disruptive Russian behavior. And that is why I think the strength and the resolve of our European friends is so striking today."

Although there are no current talks about further European sanctions against Russia, the possibility many be up for discussion during an EU summit later this week.

Lisa Bryant, for VOA news, Paris.

President Trump unveiled his plan to combat the nation's opioid addiction crisis on Monday.

In a speech, he vowed to help create what he called "a generation of drug-free children." He said in order to win, it's important to "get tough" on drug dealers.

"If we don't get tough on them," he said, "we are wasting our time." "And that toughness includes the death penalty," he said, to which the audience responded with applause.

Trump lamented that under the current law, a dealer could sell a drug that could kill thousands during their lifetime but only get a short prison term.

You can find more on these and other late breaking and developing stories, from around the world, around the clock, at voanews.com and on the VOA news mobile app. From the world headquarters of the Voice of America in Washington, I'm Jonathan Jones, VOA news.

That's the latest world news from VOA.