Polls have opened in Uganda's presidential and parliamentary elections, though voting has been disrupted by logistical delays in parts of the country amid an internet shutdown.

In the morning, the BBC observed growing frustration among voters queuing at some polling stations in the capital, Kampala, where voting had yet to start. Election officials are yet to comment.

The delays have been blamed on failures of biometric identification kits, which some have linked to the network outage, as well as a lack of equipment in some places.

In the presidential race, Yoweri Museveni, 81, who has been in power since 1986, is seeking a seventh successive victory while facing a challenge from a charismatic pop star.

Where voting has occurred, malfunctioning biometric machines designed to verify voters' identities have complicated processes in various areas. Reports suggest that delays were also caused by polling materials failing to arrive timely.

The electoral commission will announce the results of the presidential vote by Saturday, with heightened security across the capital amid fears of potential violence.

The internet blackout imposed ahead of voting day has been condemned by the UN human rights office, highlighting growing concerns over political repression in the run-up to the elections.