UPPER EAST SIDE, Manhattan (PIX11) — A security guard at a Chase Bank on Manhattan’s Upper East Side was stabbed in the neck Friday morning, leaving the victim in what police described as critical condition.

The victim was on duty at the Chase branch on East 86th Street near Second Avenue when the attack occurred around 9:05 a.m., authorities said.

It all started before the bank opened, around 8:30 a.m. A customer was trying to get into the building but was told by the security guard the bank was not open yet and he had to come back at 9 a.m. At the same time, bank employees were arriving for work, police said.

The customer questioned why they were being let in and not him. The guard explained that they worked at the bank, according to police.

Once the bank opened, the customer went inside to make a transaction but there was an issue and the teller gave him a number to customer service, police said. The customer then allegedly started arguing with the teller and a bank manager got involved.

The customer was asked to leave and the security guard stepped in to escort him out. The customer then stabbed the guard in the neck, police said.

Sources told PIX11 News surveillance video from inside the bank shows the attack as well as employees frantically trying to help the security guard.

After the attack, police said the suspect ditched his scooter and ran off. No arrests had been made, as of Friday evening.

A spokesperson for Chase released a statement Friday: “Our thoughts are with the security guard and his family and we are cooperating with police.”

Submit tips to police by calling Crime Stoppers at 1-800-577-TIPS (8477), visiting crimestoppers.nypdonline.org, downloading the NYPD Crime Stoppers mobile app, or texting 274637 (CRIMES) then entering TIP577. Spanish-speaking callers are asked to dial 1-888-57-PISTA (74782).