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

At 08:00 local time (05:00 GMT), the BBC observed that things had yet to get going at five polling stations in the capital, Kampala, an hour after voting was due to start.

The delays have been blamed on failures of biometric identification kits, which some have linked to the network outage.

In the presidential race, Yoweri Museveni, 81, who has ruled the country for nearly four decades, is seeking a seventh successive election victory as he faces a challenge from a charismatic pop star.

Where voting has been taking place, there are reports that the biometric machines used to verify voters' identities are still malfunctioning in some areas.

Some biometric machines are not working. I don't know if it's the internet, a ruling party official told AFP news agency.

The problems appear to be affecting areas that are seen as pro-government as well as areas that are seen as pro-opposition.

The poll is essentially a two-horse race between Museveni and singer-turned-politician Bobi Wine, but given the president has won the six previous elections, analysts say he is likely to further extend his time in power.

Internet access had been suspended ahead of voting day, with Uganda's Communications Commission saying a blackout was necessary to prevent misinformation, fraud, and incitement of violence - a move condemned by the UN human rights office as deeply worrying.

Polling is due to close at 16:00 local time (13:00 GMT), with results expected by the same time on Saturday.