Sudan's president arrived in Beijing for talks with Chinese officials on Tuesday, a day after his plane was forced to turn back over Turkmenistan because of flight itinerary problems.
China is a major economic partner for Sudan, and Beijing extended the invitation to President Omar al-Bashir despite an international warrant accusing him of war crimes.
Sudan's Foreign Ministry said al-Bashir's flight from the Iranian capital Tehran was delayed. The delay forced the rescheduling of a meeting with Chinese President Hu Jintao.
The reasons why the plane had been redirected were not fully explained, but apparently there was confusion over the flight plan .
Sudan's Foreign Ministry said in a statement carried by the official Sudan News Agency that al-Bashir's plane had been instructed to change its route while flying over Turkmenistan but was unable to do so, and instead returned to Tehran.
The website of the France-based Sudan Tribune cited unnamed sources as saying the presidential plane's flight path was abandoned after it was "deemed risky" but didn't elaborate.
Chinese Foreign Ministry official Guan Enxia said al-Bashir's meetings with Hu and other Chinese leaders had been pushed to Wednesday.
Al-Bashir is wanted by the International Criminal Court for allegedly orchestrating atrocities in Sudan's Darfur region on the first such warrant against a sitting head of state.
The Netherlands-based court has no police force and relies on member states to execute its orders and warrants. China is not a member.
The Sudanese leader rejects the charges, and China, which has major oil investments in Sudan, has expressed concerns the indictment of al-Bashir could further destabilize the region.
Amnesty International earlier said China should withdraw its invitation to al-Bashir and arrest him if he travels to Beijing.
"If China welcomes Omar Al-Bashir, it will become a safe haven for alleged perpetrators of genocide," said Amnesty's Deputy Asia Pacific Director Catherine Baber.
Al-Bashir has traveled without arrest to several other nations, including ICC treaty signatories Chad and Kenya.
His talks with Chinese leaders are expected to focus on promoting peace in the African nation ahead of south Sudan's independence next month.
Violence has escalated in areas contested by the north and soon-to-be-independent south, and China is pressing both sides to peacefully settle the disputes, Beijing's special envoy for African affairs Liu Guijin said last week.
China has long had close ties with the leaders of the north. It has been courting support in the oil-producing south, which becomes an independent country July 9.
In an interview with China's state-run Xinhua News Agency before he left Sudan, al-Bashir said the split would not affect relations between Sudan and China, even if Beijing were to establish relations with the southern Sudan state.
He praised China as an oil partner, calling the agreements with Chinese companies a "real exchange of benefits," while saying deals with Western companies were unfair.
South Sudan's declaration of independence next month will be the culmination of a 2005 peace deal that ended more than two decades of civil war that killed more than 2 million people.
Associated Press writer Mohamed Osman in Khartoum, Sudan contributed to this report.