Police investigating the deaths of two 17-year-old boys at a birthday party at a house in Milton Keynes say they believe it was a targeted attack.

One of the boys died at the scene and the other was taken to hospital where he died early on Sunday. Police said masked assailants arrived uninvited at the party and perpetrated the stabbings in was believed locally to be a gang-related incident.

As detectives made further appeals for information on Monday, an increased police presence remained at the scene in Emerson Valley, with officers conducting house-to-house inquiries.

“We know that the party was a private birthday party, and although we believe that all of those involved were known to each other, we believe that those responsible arrived at the party uninvited, wore face coverings and they were armed with knives in what appears to be a targeted attack,” said Det Ch Supt Ian Hunter of Thames Valley police.

“We are following a number of active lines of inquiry at this time, including speaking to those who were guests at the party and the two injured victims. Whilst no arrests have yet been made, we are working around the clock to make arrests and are continuing to search relevant places.”

He added: “I have a clear message to those responsible. We are looking for you and I urge you to hand yourself into a police station as soon as possible. I also wish to remind anybody that might be assisting or asked to assist those responsible that it is a criminal offence to do so and can lead to prosecution.”

The victims have been named locally as Dom Ansah and Ben Gillham-Rice. Postmortems are due to take place on Tuesday.

Two other males, a 17-year-old and a 23-year-old, were injured during the incident. One has been discharged, and the other is recovering from his injuries.

Thames Valley police are also investigating an alleged GBH incident after officers were called to an address in Greenleys, on the outskirts of Milton Keynes, on Sunday night after reports that a man had been stabbed. It was unknown whether this was a retaliatory attack.

The Conservative MP for the area, Iain Stewart, tweeted: “I am shocked by this double murder in my constituency. I offer my deepest condolences to the families affected and am available to offer them assistance. I shall also be speaking to the police to understand the circumstances behind the crimes.”