The U.N. ambulance carried an urgent patient: a local woman in labor. South Sudan government soldiers stopped the ambulance 15 times at checkpoints in the capital, Juba. The Aug. 2 journey, which usually takes 15 minutes, lasted nearly two hours.

"The baby was dead on delivery," says a confidential report from U.N. Secretary-General Ban Ki-moon to the U.N. Security Council. The report, obtained by The Associated Press, is a stark list of the ways South Sudan's government has obstructed the U.N. peacekeeping mission in a country devastated by civil war.

In one incident last month, two South Sudanese soldiers stopped a U.N. vehicle and threatened to kill the international staffers inside, the report says. In another, soldiers in the capital beat the driver of a U.N. truck "with an electric cord."

The report is the first by the U.N. chief since the Security Council gave South Sudan's government an ultimatum in mid-August: Allow the deployment of a 4,000-strong regional protection force and let the existing U.N. mission do its job unimpeded, or face a possible arms embargo.

While South Sudan's government agreed to the regional force during the council's visit to the country early this month, its officials have spoken out against it, saying it violates the country's sovereignty. Hostility against the international community inside South Sudan has grown.

The report from the U.N. chief, dated Sept. 8, calls the situation "unacceptable."

Under a resolution the Security Council approved in August, Ban's list of South Sudan government obstructions of the U.N. peacekeeping mission was meant to trigger a council meeting within five days to consider imposing an arms embargo and other options.

But there has been little outcry from council members, who discussed South Sudan on Sept. 14 only behind closed doors.

Under the terms of the U.N.'s operating agreement in South Sudan, its peacekeeping mission is allowed free movement throughout the country. Ban's report to the Security Council, which describes incidents during the month of August alone, shows how that agreement appears to be failing.

Of the 22 incidents listed by the U.N. chief, almost all describe South Sudan security forces denying passage or access, at times also making threats or extorting money.

South Sudan was operating under a fragile peace deal when fighting erupted again in Juba in July. Dozens of rapes and other attacks on both civilians and foreigners in the capital led to calls for the new regional protection force.

The world's youngest country, which gained independence in 2011 from Sudan, saw civil war break out in December 2013. Tens of thousands of people have been killed, and both President Salva Kiir and rebel leader Riek Machar have been accused of war crimes. Machar fled the country during the July fighting and over the weekend issued a call for rebellion from his new location in Sudan.