Updated

Secretary-General Ban Ki-moon is backing the concerns of international observers about shortcomings and irregularities in Uganda's elections and is urging all parties to settle any disputes peacefully.

U.N. spokesman Stephane Dujarric said Tuesday that Ban calls on Ugandan authorities to ensure that all election-related claims and concerns "are handled in a fair, expeditious and transparent manner."

Neutral observers criticized Uganda's government for using security forces against opposition candidates and supporters. Tensions rose Monday when police arrested President Yoweri Museveni's main challenger, Kizza Besigye.

The U.N. human rights office expressed concern Tuesday at reports of at least two people killed, heavy military and police forces deployed in the streets of the capital Kampala, and the arrest of four opposition leaders since Thursday's elections.