Customers have reported being unable to access the internet and other services across the network.
"The faulty software that has caused these issues is being decommissioned and we apologize not only to our customers but also to their customers", Ekholm said.
It is not clear when the issue will be resolved, but O2 said it would share further updates as soon as possible.
'A statement reads: "The network issue we are now experiencing remains a top priority for us and we are working as quickly as possible to fix the issues".
Among them are busses, which uses mobile data to transmit timetable information to smart screens on London's network of bus stops, and taxis companies which use mobile apps to get custom and dispatch cars.
Tens of millions of smartphone users in Britain lost internet access today after a software glitch brought down O2's data network.
The network blamed a software issue from a third party supplier, issuing a statement confirming their service was down.
In total, around 32 million customers are affected.
A tweet sent out this morning adds: "One of our 3rd party suppliers has identified a software issue in their system". "We are working closely with the remaining customers that are still experiencing issues".
O2 chief executive Mark Evans said his teams were working hard with Ericsson to find a swift solution.
Other mobile networks, including Sky, Tesco and Giffgaff, were also affected by the problem because their networks use O2 services.
On Thursday evening, O2 said 3G data service had started returning and was expected to be fully restored by 9.30pm, while the company reported at 3.30am on Friday that the 4G network had been restored. Work is now ongoing to fix the fault and customers are being encouraged to use wi-fi where possible.