A man has tragically died in a crash on the Britannia Bridge between Bangor and Anglesey on Thursday morning.
Emergency services were at the scene following the incident, which happened shortly before 3.00am.
North Wales Live has confirmed that another man is seriously injured. A man has also been arrested following the early morning tragedy.
Diversions are still in place, with the closure stretching from Junction nine for the Treborth area in Bangor, Gwynedd to Junction eight on Anglesey.
North Wales Police has said that "significant traffic disruption" will lead to some delays on the roads in the Bangor area this morning and have urged motorists to avoid the area if they can.
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North Wales Fire and Rescue Service has said that four vehicles were involved in a "serious crash".
A spokesperson for the fire service said: "We were called at 2.56hrs this morning to a serious RTC involving 4 vehicles on the A55 west bound Junction 11 Llandegai to Junction 8a Britannia Bridge – 3 appliances attended.
"We assisted with extrication of casualties using Holmatro equipment. Police and Ambulance also in attendance. Road was closed in both directions."
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