A U.S. gunman opened fire at a house near Atlanta, Georgia on Saturday, killing four people and wounding two children including relatives in a domestic dispute before turning the gun on himself.

A total of seven people were shot in the case in Douglasville, west of Atlanta, said Lieutenant Glenn Daniel of the Douglas County Sheriff's Office.

The United States is weighing "additional" assistance to Ukraine as it battles Russian-backed separatists, Secretary of State John Kerry said Saturday, while stopping short of saying Washington would send arms.

Kerry's comments came as Western leaders challenged Russian President Vladimir Putin to prove he wants peace in Ukraine, warning both sides a new Franco-German peace drive may be a "last chance" to stop all-out war.

A man convicted of murdering his girlfriend in 1999 and featured in a recent hit U.S. podcast will be given a chance to appeal his sentence, a Maryland court said in a decision made available Saturday.

Adnan Syed, 34, was sentenced to life imprisonment in 2000 for the murder of his former girlfriend Hae Min Lee.

A Lebanese professor at the University of South Carolina's school of public health was reportedly killed in an apparent murder-suicide on Thursday.

The deaths occurred at the university's school of public health.

The Islamic State group said a coalition air strike Friday killed an American woman it was holding hostage in Syria, in a claim that could not be immediately verified.

In Jordan, meanwhile, thousands of people marched to demand retribution against IS for murdering a captive pilot.

Greece must cooperate with Europe and the IMF to draw up a plan of reforms consistent with the country's international obligations, the U.S. ambassador to Athens said Friday.

"The United States believes that it is very important for the Greek government to work cooperatively with its European colleagues, as well as with the IMF," US Ambassador David Pearce said after two days of talks with new Prime Minister Alexis Tsipras and other Greek officials.

Somalia on Friday confirmed the death of Shebab commander Yusuf Dheeq in a U.S. drone strike south of Mogadishu last week.

"The killing of terrorist leaders through precision, low risk strikes such as this one, increases the opportunities for bringing peace and stability back to Somalia," the government said in a statement.

The United States will not fully reactivate its military alliance with Thailand as long as the junta-controlled country refuses to restore democracy, a U.S. diplomat warned Thursday.

"There has to be a full restoration both of the institutions of governance and justice as well as the full restoration of a duly democratically elected civilian government," the senior State Department official told journalists.

The family of journalist Austin Tice, missing in Syria since mid-2012, said Thursday they believe he is alive as they stepped up a campaign to win his release.

They unveiled a campaign that will feature digital #FreeAustinTice banners on hundreds of websites of major media groups later this month.

U.S. Secretary of State John Kerry is to hold talks with his Iranian counterpart on efforts to secure a deal over Tehran's nuclear drive, a U.S. official said Thursday.  

"Secretary Kerry will meet with Iranian Foreign Minister (Mohammad Javad) Zarif in Munich, Germany on Saturday to discuss the ongoing nuclear negotiations," a senior State Department official said.