The US will not observe Uganda's Thursday's general election after 75% of its election observer accreditation requests were turned down by the electoral commission.

Ambassador Natalie Brown says the commission provided no explanation for its decision despite multiple requests.

She said in a statement that only "a small, randomly selected handful of our observers" were approved from a team of 88 observers.

"Absent the robust participation of observers, particularly Ugandan observers who are answerable to their fellow citizens, Uganda’s elections will lack the accountability, transparency and confidence that observer missions provide," she added.

Ugandans will be electing a new parliament and president in the election. President Yoweri Museveni, who has been in power for 35 years, will be seeking a sixth term.