A plan to move Belfast Zoo's remaining elephants to the Netherlands is "not a done deal," according to the Dutch zoo's manager.
Asian elephants Dhunja and Yhetto have been residents in Belfast since 2009.
Earlier this week Belfast City Council gave permission for them to travel to Royal Burgers' Zoo in Arnhem, following a recommendation.
However, the manager of the Dutch zoo has said he is now unsure whether or not the elephants will be moved.
Checks, assessments and post-Brexit paperwork will be a big hurdle to the move, according to Arun Idoe.
"We're not sure if we're going to move the elephants from Belfast to Holland," he explained.
"We started the initial talks with Belfast Zoo and one of the things that had to be taken (into consideration) was permission from Belfast council to move these two elephants."
Like Belfast Zoo, Burgers' Zoo is a retirement home for elderly adult cow elephants within the Elephant European Endangered Species Programme (EEP) , the manager said.
"The need for retirement homes is luckily decreasing, but we still have some old cows within the EEP that you cannot rehome into a herd.
"That's why the EEP has a couple of facilities that can be used as retirement home for these individuals and at the moment we have two other old cows - one is almost 59, the other is 55.
"If they are being moved to our zoo, first we will visit Belfast to assess the individuals to discuss their character and see if we can integrate them with the two cows we have currently at our facility.
"If we think it's a match with the cows that we have, if Belfast Zoo agrees with us being the retirement facility, we put everything in process to get it sorted - but that's never a guarantee in life."
'Take it step-by-step'
Mr Idoe said other steps to consider will be assessing the health of Dhunja and Yhetto ahead of any potential move and assessing relevant paperwork.
He said zoos will normally follow EEP recommendations as and when they are made but the recommendation to move Belfast's elephants to the Netherlands, he said, is "not so clear".
That is because "we are talking about old elephants (that are) not part of the reproduction population," he said.
He added: "So, with regards these two elephants we started the initial talks and we take it step-by-step".
Belfast Zoo has housed elephants for almost 90 years.
The first elephant, Daisy, arrived in 1934 and was walked from the docks to the zoo's site on Antrim Road, a distance of around six miles.
Manager Alyn Cairns said the main reason for moving Dhunya and Yhetto was due to the current herd size.
"What we have is two elephants - the minimum herd standard is four elephants," he said.
"The zoo that's being recommended has the potential to take our two elephants."
Mr Cairns said the reason they have "come to a crossroads" is because the Belfast elephants are in the same age bracket as the Dutch zoo's pair and are considered older and non-breeding.
BBC News NI understands a 2019 audit of Belfast's elephant enclosure raised issues regarding some elements of the facilities for the animals - these included no outdoor pool, scratching posts and the need for modernisation.
"I don't have any concerns about our elephants in respect of where we stand now," Mr Cairns said.
"There are things, of course, that we would like to improve on and I would love to have an elephant house that is 20 times bigger than this, but we don't. We have what we have."
"Our elephants don't have pools but they have showers which the elephants can press buttons of and turn on and off themselves", Mr Cairns added.
Without investment, the zoo would not be able to bring breeding elephants into its collection, Mr Cairns said.
"Elephant welfare standards are continually progressing and I want to make sure that we follow on with that," he added.