From Washington, this is VOA news. I'm David DeForest reporting.

Turkish President Recep Tayyip Erdogan says his government is ready to join any future American-proposed operation to liberate the Syrian city of Raqqa from the Islamic State group.

Turkish media say Mr. Erdogan made the remark to journalists traveling home with him from the G-20 summit. They say he told them the issue was brought up by U.S. President Barack Obama during their talks on the sideline of the summit in China.

Diplomats says prospects for peace in Syria remain uncertain Wednesday after the broad-based opposition group, the High Negotiating Committee, presented its blueprint for a political transition in Syria.

British Foreign Minister Boris Johnson called the meeting with the opposition group in London, saying there is still a chance to plan for a political transition in Syria.

"It is obviously critical that the world and all the interlocutors in Geneva should be able to see that there is a future for Syria that goes beyond the Assad regime."

The 25-page plan HNC leaders presented on Wednesday is unlikely to be implemented as long as Russia and the United States are unwilling to compromise on their support for the two opposing sides.

About 100,000 people in Syria's central Hama province have been forced from their homes by fighting between government forces and insurgents.

The United Nations Office for the Coordination of Humanitarian Affairs says nearly half of the displaced from the province are now in neighboring Idlib province, which is held by the rebels.

It says others are in government-controlled Hama city, where four mosques have been converted into temporary shelters.

This is VOA news.

The United States is accusing Russia of sending one of its fighter jets dangerously close to an American spy plane over the Black Sea on Wednesday. American military officials said the intercept was "unsafe and unprofessional." Russia insists it acted in accordance with international flight rules.

The U.S. says a Russian jet flew within three meters of the American plane for 19 minutes.

U.S. President Barack Obama Wednesday told a group of young people gathered from across Southeast Asia "it is not enough to dream about your plans. You have to actually do some work."

"The world has never been healthier, it's never been wealthier, it's never been better educated. It's never been less violent, more tolerant than it is today."

In an upbeat town hall event in Laos with people involved in the U.S.-sponsored Young Southeast Asian Leaders Initiative, Mr. Obama said young people have historically been the key to progress and development. He stressed the need for countries to improve education standards and to make sure those gains include girls, not just boys.

The Philippines government [established] published, rather, photos Wednesday of what appears to be Chinese naval ships building an island in the contested South China Sea.

Those photos showed an increased number of ships and what the Philippines says is evidence of "fresh" construction of an artificial island near Scarborough Shoal. The photos were released just before the annual meeting of the 10-member Association of Southeast Asian Nations.

China denies the accusations, saying it has simply (quoting now) "maintained a number of coast guard vessels for law enforcement patrols" in the area.

In a likely preview of their three upcoming debates, presidential candidates in the U.S., Hillary Clinton and Donald Trump, will appear on the same stage Wednesday night to talk about national security.

Democratic presidential candidate Hillary Clinton and Republican nominee Trump will appear separately at a forum sponsored by NBC news and take questions from an audience, primarily of veterans and active U.S. service men and women.

Both have spent the campaign trading accusations that the other is unqualified to be commander in chief.

Trump today told supporters he believes several countries are providing a military challenge.

"China has grown more aggressive, and North Korea more dangerous and belligerent than ever. Russia has defied this administration at every single turn. Putin has no respect for President Obama and has absolutely no respect for Hillary Clinton."

Clinton and Trump will hold their first face-to-face debate September 26.

The U.S. conducted two airstrikes in southern Somalia this week. Four al-Shabaab militants were killed in the attacks.

From the VOA news center in Washington, I'm David DeForest.

That's the latest world news from VOA.