Ten people have been arrested on suspicion of murder after a police officer was killed while responding to a reported burglary in Berkshire.
The victim has been named as PC Andrew Harper from the Roads Policing Proactive Unit based at Abingdon Police Station.
Police have confirmed that a 13-year-old boy is among the ten males who have been arrested and are currently being held in custody at different police stations across the region.
Thames Valley Police said the "serious incident" happened at 11.30pm on Thursday near the A4, Bath Road, between Reading and Newbury.
It occurred at the crossroads off Ufton Lane and Lambdens Hill, near to Sulhamstead.
The nearby A4 Bath Road was reopened on Friday morning, but Ufton Lane and Lambdens Hill are still closed.
Andy Fiddler, from Thames Valley Police Federation, reflected on the "devastating news" of the loss of a colleague.
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He said: "All our thoughts – and the thoughts of the entire police family across the UK – are with the family, friends and close colleagues of PC Andrew Harper, who died last night.
"Police officers go to work each and every day to do their duty. We are courageous, caring and compassionate. We confront danger on a daily basis. We know there is a risk when we put on the uniform but we do so as we are proud to protect the public.
"Sadly on very rare and horrendous occasions a colleague makes the ultimate sacrifice. We will ensure that heroism is never forgotten."
Anthony Stansfeld, the police and crime commissioner for Thames Valley, said he was sending "deepest condolences" to the family and friends of Mr Harper.
He added: "This is a tragic loss for the force and I know that Thames Valley Police are doing all they can to support those who have been affected."
Meanwhile, Home Secretary Priti Patel tweeted: "My thoughts are with the family of PC Andrew Harper who was killed in the line of duty last night."
Labour MP and shadow policing and crime minister Louise Haigh also tweeted about the "horrific news", adding: "[Although] it won't bring him back, I hope the culprit is swiftly brought to justice."