Media playback is unsupported on your device Media caption The 2015 video shows the police officer pinning down a teenager

A police officer filmed in a 2015 confrontation with a black teenager at a pool party in Texas is being sued for $5m in damages for false arrest, assault and excessive force.

The lawsuit names the city of McKinney, its police department and former police officer Eric Casebolt.

Teenager Dajerria Becton was 15 when she was filmed being forcibly held face down by Mr Casebolt.

A McKinney city statement on Wednesday denied the allegations.

"The City of McKinney denies the claims alleged against it and the McKinney Police Department, and as such, will vigorously defend the recently filed lawsuit," a statement said.

"McKinney prides itself in cultivating the highest standards of training and professionalism for our officers, and it strongly believes that its standards and training will withstand legal challenge."

The teenager's lawsuit argues that the city and the police department are responsible for her injuries because it did not properly train its officers, the Dallas Morning News reported.

The lawsuit - filed on her behalf by her family - says Mr Casebolt held her down with one knee on her back and one on her neck. It points out that she was invited to the party and did not break any laws.

Image copyright Reuters Image caption Tensions over alleged police brutality have run high in McKinney since the 2015 incident

In June 2015 Mr Casebolt's lawyer argued that he was acting out of stress, not racism.

Before arriving at the pool party he had responded to a suicide call where a black man shot himself in the head in front of his wife and children.

Mr Casebolt resigned from the police force four days after the pool party incident. His actions were described as "indefensible" by his former boss.

The video showed the officer throwing a girl in a bikini to the ground, then pulling a gun on other bystanders.