Thousands of Sudanese government troops and ex-rebel fighters were deployed, meanwhile, in the south’s main town of Juba amid high tensions and intense emotions on the eve of Garang’s funeral.
“Some people say accident, it may be an accident, it may be something else,” President Yoweri Museveni said, becoming the first official of any government to publicly suggest Saturday’s crash may have been the result of foul play.
“The (helicopter) was very well equipped, this was my (helicopter) the one I am flying all the time, I am not ruling anything out,” he said, noting an international panel of experts had been appointed to look into the crash.
“Either the pilot panicked… either there was some side wind or the instruments failed or there was an external factor,” Mr Museveni told mourners in Yei where Garang’s body was brought ahead of his Saturday funeral in Juba.
Garang’s successor as chief of the Sudan People’s Liberation Movement/Army (SPLM/A), Salva Kiir, declined to comment on Mr Museveni’s remarks but said the group was eager to hear the results of the probe.
“All options are open and cannot be ruled out,” Mr Kiir told reporters after calling on mourners to reject the violence that has engulfed parts of Sudan since Garang’s death and urging them to hold to their ex-leader’s vision for peace.
“Let us follow the footsteps of our leader,” he told the crowd.
“This is not the time for rioting,” Mr Kiir said, blaming unspecified opponents of peace for wanting “to provoke a situation that would lead us back to war.”
In Khartoum and Juba, senior SPLM/A officials cautioned against making any assumptions about the cause of the crash as did a diplomat in Bor, Garang’s birthplace where his coffin was brought after Yei.
But Sudanese Foreign Minister Mustafa Osman Ismail later called on Uganda to cooperate with the investigation into the crash.
“(Garang’s) visit was to Uganda and the aircraft and its crew was Ugandan,” Mr Ismail told the official SUNA news agency.
However, he expressed displeasure that the Ugandan authorities informed Sudan about the disappearance of Garang’s helicopter several hours after they found out.
Garang and 13 others died when Mr Museveni’s presidential Mi-172 helicopter went down in the mountains of southern Sudan, sparking days of violence in Khartoum and the south that saw 130 killed and hundreds wounded.
His death and the rioting raised fears of the unraveling of the landmark January peace deal he signed with Khartoum that ended Sudan’s 21-year north-south civil war.
However, relative calm returned to the streets of Khartoum on Friday as shop-owners reopened for business amid a noticeably lower security presence.
Many southerners believe Garang was somehow assassinated and have refused to believe the initial insistence of Ugandan, Sudanese and other officials that the helicopter went down because of poor weather.
Mr Museveni did not elaborate on what he meant by “external factor” but there has been widespread speculation in southern Sudan that the chopper may have been somehow sabotaged or shot down.
In a bid to quell the speculation and restore calm, Sudanese President Omar el-Beshir has launched a formal probe that Mr Museveni said would be joined by aviation experts from Uganda, Kenya, the United States, Britain and Russia.
As preparations for the massive send-off continued, two plane loads of heavily armed Sudanese soldiers, including members of the elite presidential guard, landed and immediately spread throughout the town.
Thousands of southern Sudanese descended on a former military training ground in Juba to help prepare Garang’s burial site ahead of his funeral on Saturday that is expected to draw some 500,000 people.