From Washington, this is VOA news. I'm David DeForest reporting. South Sudan's rival leaders call on their forces to halt the fighting which threatens to tear apart a fragile peace agreement and unity government.

The violence continued Monday in South Sudan's capital, Juba, as we hear from Jason Patinkin.

South Sudanese government troops shelled the United Nations compounds in Juba Monday where nearly 30,000 civilians had taken shelter from the country's war, causing dozens of casualties.

Government forces called SPLA and armed opposition called SPLAIO have fought in the city for the past four days.

Several hundred people have been killed, including civilians.

Much of the fighting Monday was in the Jebel area near a U.N. base.

There was also fighting near the airport which has been shut down to all flights.

Jason Patinkin, Nairobi.

United Nations Secretary-General Ban Ki-moon Monday urged the Security Council to impose an arms embargo and targeted sanctions on South Sudan.

Defense Secretary Ash Carter says the U.S. will send 560 troops to help the Iraqi government retake the city of Mosul from the Islamic State group.

Carter spoke Monday during a visit to Baghdad. "This contingent will help the Iraqis establish a logistical springboard for their offensive in Mosul, which Prime Minister Abadi reaffirmed to me that he wants to accomplish this year." :Ash Carter.

Opposition fighters in northern Syria launched a major offensive Monday against government-controlled areas of Aleppo.

The action came just days after government troops seized the only supply road into the opposition sector of the city.

Monitors said the rebel operation began at dawn on several fronts. The Britain-based Syrian Observatory for Human Rights said 19 troops loyal to the president were killed.

This is VOA news.

British Prime Minister David Cameron said he will officially resign on Wednesday, allowing Interior Minister Theresa May to become the country's next leader.

May stepped in line to be the next prime minister when her only remaining rival for the post, Energy Minister Andrea Leadsom, withdrew from the race.

"I'm delighted that we're not going to have a prolonged Conservative leadership election campaign. I think Andrea Leadsom has made absolutely the right decision to stand aside and it's clear Theresa May has the overwhelming support of the Conservative Parliamentary Party."

Mr. Cameron said on Wednesday he will attend the House of Commons for prime minister's questions and then go to the palace to offer his resignation.

U.S. Secretary of State John Kerry will travel to Russia this week. A State Department spokesman says Kerry will discuss the situation in Syria and Ukraine as well as tensions between Armenia and Azerbaijan over the Nagorno-Karabakh region.

Kerry will travel to Moscow on Thursday after taking part in Bastille Day celebrations in France.

U.S. President Barack Obama plans to visit Dallas, Texas, on Tuesday to attend a memorial service for the five white policemen killed by a black sniper. The president is calling on Americans to respect each other.

Meanwhile, demonstrations have been held in many U.S. cities across the country in the last several days against what the protesters believe are the unjustified killings of black suspects by police officers.

Presumptive Republican presidential candidate Donald Trump declared himself the "law and order candidate" Monday. Trump told a rally in Virginia that the country has to end hostility toward police and improve life for people in crime-ridden inner-cities.

Meanwhile, presumptive Democratic presidential nominee Hillary Clinton will be joining Democratic rival Senator Bernie Sanders at a campaign rally in Portsmouth, New Hampshire, on Tuesday.

There is widespread speculation that Sanders might just endorse Clinton at the rally.

Thousands of Venezuelans streamed across the border into Colombia on Sunday to purchase essential goods that have become impossible to find or purchase in their home country. Many goods are in short supply in Venezuela because of a severe economic crisis.

Venezuelans were able to stock up on items in Colombia that have become almost impossible to find or afford in Venezuela, such as flour, oil, toilet paper, shampoo and medicine.

Thousands of people defied a curfew and took to the streets for a third day in Indian Kashmir. They are protesting the killing of a local separatist leader.

The death toll in the unrest has climbed to more than 25. Hospitals have been overwhelmed by the number of hurt (in) fighting with security forces who opened fire and lobbed tear gas. The wounded included many policemen.

In Washington, I'm David DeForest.

That's the latest world news from VOA.