Tanzanian side Simba say they will not take part in the east and central African regional Cecafa Club Championship if it is held in Darfur, Sudan as planned.
The decision follows questions over security in the troubled region being raised by Tanzania's foreign minister Bernard Membe in parliament over the weekend.
"Cecafa should change the venue otherwise we will not go to Darfur to put on bullet proof vests," Simba chairman Ismail Adne Rage said.
"It is obvious that there is a state of insecurity as confirmed by the government."
Membe had expressed his surprise that the tournament was being hosted in war-torn Darfur.
"I was shocked by Cecafa decision to take the competition to Darfur," the minister said.
"The government is studying this situation and we promise to make a firm stand on this, we cannot send our boys to a place where their security could be compromised."
Defending champions Yanga, who had earlier said they were happy to go to Darfur, said they would now follow government advice.
Tanzania Football Federation Secretary General Angetile Osiah said they had been assured of security and accommodation despite the government's concerns.
"Cecafa has assured us that security is okay and accommodation is good. We also saw pictures on Supersport and it looked okay," he old BBC Sport.
"However, the government has the final say on this and we will have to go with what they advise," he added.
The possible withdrawal of the two Tanzanian sides would be another massive blow to the credibility of the tournament following the decisions of Sudan's two biggest clubs Al Hilal and Al Merreikh not to participate last month.
Ethiopian champions St George also opted not to take part in order to concentrate on their Confederation Cup campaign.
The secretary general of the regional body Cecafa, Nicholas Musonye, insisted last month that Darfur is safe to host the event.