Some people sat in the trees along Chebucto Road to prevent crews from chopping them down. (CBC)

Police arrested six people Friday after protesters climbed trees to prevent the start of a contentious road expansion in Halifax.

The four men and two women face charges ranging from mischief to obstructing police to assaulting a police officer, police said.

About 60 protesters gathered on Chebucto Road as workers with chainsaws prepared to cut down trees, the first step in widening the road.

Police officers pushed back the crowd to keep everyone away from falling tree limbs.

Halifax police arrested several people at the protest on Chebucto Road. (CBC)

Some people cried and others yelled as a grinder chopped up branches.

It took about 20 minutes to take down the first tree. Workers say they will be back Monday to cut down the remaining six trees.

The plan to widen Chebucto Road calls for a third lane to allow for an extra 300 cars every hour, a development the municipality says will ease traffic coming off the nearby Armdale roundabout.

The expansion, approved by Halifax regional council, has been fiercely opposed by some local residents and their supporters.

On Wednesday, opponents called for a seven-day moratorium on construction, however, the municipality said work would go ahead as planned.

Police said the six people arrested would be released once they determined individual charges.

None of them live in the neighbourhood affected by the street widening, police said.