Updated

Ugandan police have fired tear gas to disperse a crowd of students protesting against plans to introduce legislation that would allow the longtime president to rule for life.

The bill is likely to be introduced in the national assembly later Thursday despite growing opposition from civic groups and opposition leaders.

On Thursday police fired tear gas at university students in the capital, and there is heavy police and military deployed across the normally calm Kampala.

Ugandan police have also besieged the offices of two NGOs that the authorities accuse of supporting anti-government protests.

Uganda's constitution bars anyone over the age of 75 from seeking the presidency.

President Yoweri Museveni, who is 73 and ineligible to run again in 2021 if the age hurdle remains, has held power here since 1986.