In the hours before President Barack Obama arrived at a Johannesburg soccer stadium to honor Nelson Mandela, the White House staff was in the dark on critical details.

Where would the president and first lady Michelle Obama sit? When was Obama supposed to speak? Who else would be on stage during the speech?

The result was an array of confusion and security risks that typically would not be tolerated by the Secret Service in the United States. The situation showed just how the Secret Service often is at the mercy of foreign governments to make arrangements when the president is overseas.

There were metal detectors and X-ray machines at the stadium, but they were not used on the initial crowds streaming in for the ceremony, according to reporters on the scene.

Many people walked through with little or no screening. Inside the stadium, there were few signs of the heavy security that routinely would accompany an event with Obama and other world leaders.

The VIP section was where Obama and dozens of other dignitaries sat, including former Presidents George W. Bush and Bill Clinton. This area was protected by a short pane of protective glass that covered only those in the first row of seats. Obama and his wife were several rows back.

Large crowds were allowed to gather in front of where Obama sat, with no visible security nearby.

When Obama made his way to the stage to deliver his speech, a South African sign-language interpreter stood an arm’s length away. This man later described himself as schizophrenic with violent tendencies, and he reportedly was accused of murder 10 years ago, according to the national eNCA TV news station in South Africa.

Secret Service officials say the South African government was responsible for the decision to place interpreter Thamsanqa Jantjie just inches from some of the most powerful people in the world during a four-hour memorial service.

“Program items such as stage participants or sign-language interpreters were the responsibility of the host organizing committee,” said Secret Service spokesman Edwin Donovan. “For the purposes of this memorial service, this would include vetting them for criminal history and other appropriate records checks.”

Brian Dube, a spokesman for South Africa’s Ministry of State Security, declined to answer questions Saturday about what security measures were in place at the soccer stadium and what sort of background checks and screening were performed on Jantjie. Dube said those issues are part of the investigation into the hiring and use of the interpreter.

Donovan said prearranged security procedures were in place Tuesday and agents were “in close proximity,” a standard security practice wherever the president is. He declined to discuss specific security details of Obama’s trip to South Africa.

The Secret Service is charged with keeping the president, vice president and their families safe. Presidential trips, whether across the country or around the world, are meticulously planned with every imaginable detail within the agency’s control managed and scheduled.

But once the president leaves the United States, the Secret Service isn’t always entirely in control.

Joe Hagin, a former deputy White House chief of staff for Bush, said that to some degree the Secret Service is at the mercy of a host government.

“There’s a lot of diplomacy involved in one of these trips,” said Hagin, now a partner at Command Consulting Group in Washington. “The White House is very demanding. But there’s a fine line in what you can demand and what you can’t.”