A person is thought to have been stabbed in West Drayton as police officers investigate at the scene.
Officers were seen in Sipson Road, near Heathrow Airport, at around 5pm on Wednesday afternoon as well as a person who was receiving treatment for their injuries.
An eye witness told getwestlondon the victim appeared to have a wound to the hand.
The witness also said officers appeared to be speaking to three people at the scene of the alleged attack.
A Metropolitan Police spokesman said officers had responded to reports of a fight in Sipson Road at about 3.45pm.
They confirmed a man in his 30s suffered a stab wound to the hand and was taken to hospital. His condition was not thought to be life-chaning.
A resident of 15 years said she had seen some of the incident.
"I heard arguing - it was loud and there was shouting," said the resident, who asked not to be named.
"I didn't hear what they were saying. I just looked out, the police came and I saw a man who was bleeding.
"He was Asian. His hands were held up and were bloody so it looked like they had been stabbed."
Earlier this week, the mother of murdered teenager Jamil Palmer issued a plea to young people to 'be leaders not followers' and stop using knives on the streets in a service held to mark two years since his death in Hanworth.
Jamil was Mr Palmer was just 18 when he was stabbed to death beside a playground in Crane Park, Hanworth, by 17-year-old Mohammed Barre in a row over wounded pride on May 6 2014.
