In a surprise decision on November 29, the EU cancelled its electoral mission to the central African nation, citing technical issues.
The Democratic Republic of Congo (DRC) is due to hold presidential and parliamentary elections on December 20. President Felix Tshisekedi, 60, is running for re-election.
The government said last week it regretted the move to cancel the observation mission.
However, several officials told AFP the cancellation came after a long-stalled request to Congolese authorities for permits for satellite equipment.
The equipment consisted of phones and internet terminals known as BGANs as well as vehicle-tracking devices intended to enable observers to stay in touch with a core team in the capital Kinshasa.
EU officials requested the permits two months ago, according to sources close to the case who requested anonymity. They said there was no response by mid-November, by when an initial team of observers had arrived in the DRC.
Brussels set a deadline for a response for midday November 29.
Shortly after the deadline passed, on the same day, Congolese officials including Interior Minister Peter Kazadi informed EU officials the request had been denied.
The Congolese officials said the equipment, notably the BGANs, could be used to manipulate electoral results, according to the sources, who described the meeting as tense.
The officials offered to allow EU observers to buy the satellite equipment domestically, with the proviso that it would be available for inspection on request.
According to the sources briefed on the case, that would not have worked because it would have raised the possibility of EU observers being deprived of communications equipment in rural areas.
Fear of foreign influence
A Congolese government spokesperson was not immediately available for comment. A spokesperson for Interior Minister Kazadi referred AFP to a Congolese government statement regretting the mission's departure.
An EU spokesperson told AFP the observers could not deploy because key equipment wasn't allowed into the country, but did not comment on Congolese government concerns about vote tampering.
"These devices are essential tools for our observers," the spokesperson said.
The election campaign has been marked by accusations that some presidential candidates are backed by foreign powers with designs on the DRC, an impoverished country with huge reserves of critical minerals such as copper and cobalt.
Critics often assert that Rwanda backs leading opposition candidate Moise Katumbi, 58, without presenting evidence.
Likewise, there is a perception in some quarters in the DRC that European states support Katumbi.
Tshisekedi came to power after a 2018 election whose results were fiercely disputed.
Congolese civil society, the US-based Carter Center and the 16-nation Southern African Development Community (SADC) will observe the election.
KINSHASA - DR Congo refused to authorise satellite equipment for European Union election observers over fears it would be used to manipulate the presidential poll later this month, several sources told AFP.