SINGAPORE - Intermittent signalling issues were responsible for train delays on the Circle Line during the morning rush hour on Monday (Aug 29), rail operator SMRT said in a statement.

The ongoing issues could delay travel time by up to 10 minutes during peak hours, until service ends for the day.

SMRT also advised commuters using the trains to hold onto the handrails, as they "may experience intermittent braking".

Mr Patrick Nathan, vice-president of corporation information and communications, said that engineers are working on fixing the signalling problem.

Commuters first reported delays after 8am, posting photographs on social media that showed crowded station platforms.

They complained of long wait times between trains at stations along the Circle Line.

Other users tweeted that faulty sensors were causing train doors to shut on commuters at station platforms.

It was not until around two hours later, at 10.15am, that commuters reported that smoother service had resumed.

"We are sorry for the inconvenience caused and we will be keeping all passengers updated through Twitter, Connect and Facebook, and through our PA systems," the SMRT statement said.

More SMRT employees have been deployed at stations to assist passengers. "Our staff will also be on board the Circle Line trains for the rest of the day," it said.