Reverend Mead Birungi, of World Shine Ministries, told World Watch Monitor that anti-terrorist police are providing security to churches in Uganda after the US embassy there warned of possible attacks.
There are also concerns of imminent attacks in Kenya and Rev Birungi said people were being informed about what explosives look like "so that they can identify them".
"We are especially concerned about the situation based on what we have seen happening in Kenya," said Rev Birungi.
British citizens were recently evacuated from Kenya over security concerns. The alert came as 10 people were killed and 70 injured in Gikomba, Nairobi, on May 16.
This was followed by a grenade attack on May 21 close to a mosque in Garissa, near the Kenya-Somalia border, in which one person was reported killed and 11 injured.
On Saturday, at least 10 people were killed when Islamist militants from the Al-Shabab movement attacked the Somali parliament in Mogadishu.
"The influx of guns and other dangerous weapons into the country is alarming," said Cardinal John Njue, chairman of the Kenya Conference of Catholic Bishops.
"Suddenly, Kenyans cannot go to places of worship without fear. A country that has for years been called the oasis of peace in the region has become a terrorist playground."