Fans at the Oval cricket ground in England have been evacuated after what was described as a "crossbow bolt" was fired on to the pitch.
Play has been abandoned in the County Championship clash between Surrey and Middlesex after the "projectile" was fired into the ground, in Kennington, south London, from outside at around 4.20pm, according to the competition's official Twitter feed.
Play suspended at Kia Oval after a "projectile" was fired into the ground from outside. Fans urged to move indoors. We'll keep you posted pic.twitter.com/LSl3mLqE7i— LV= Insurance County Championship (@CountyChamp) August 31, 2017
One witness described seeing players and umpires running off the field before fans were told to move inside, and pictures on social media appeared to show armed police on the scene.
Another spectator claimed officers told him they believed two arrows were fired into the grounds but police have yet to confirm this.
Scotland Yard said the 1,068 spectators were evacuated, there were no reports of any injuries and officers had an "open mind" about the motive.
Umpire Paul Baldwin was pictured holding the pink-coloured bolt, with red and yellow fletching.
Middlesex County Cricket Club tweeted: "Players have left the field after a crossbow bolt landed on the square.
"Understandably, after the earlier suspension of play, the game at the Oval has been abandoned with the game ending as a draw."
A Surrey spokesman told the Press Association all fans had to take cover on the concourse.
He said: "We were about to bowl the next ball and the arrow appeared two pitches to the side of the pitch we're playing on at the moment.
"The umpires took it out of the ground and got the players off as quickly as possible."
"We're not sure if it's deliberate or accidental or whether it's come from inside or outside the ground."
David Schofield, from London, said he had been told by three armed officers that it is believed two arrows were fired into the grounds.
He said: "They said there were two fired from the north east corner of the OCS stand of which one, they think, hit the roof.
"They were definite it was from outside the stand."
He added: "I thought play had been delayed because the light was getting a bit bad or there might have been a sporting declaration by Middlesex - that was not the case.
"Eventually announcements were made and we were told to get inside."
Middlesex fan Jeremy Lawrence saw players being rushed off the pitch shortly after the arrow landed.
He said: "I was sitting by the players' entrance talking to a fan and all of a sudden I saw all of the players and the umpires run off the pitch.
"I thought, 'it's not raining, what's going on?' and one of the Surrey cricketers, Rikki Clarke, said 'somebody's fired an arrow on to the pitch'."
Mr Lawrence said he thought it looked "like a crossbow arrow", and that nobody was sure where it had come from.
"It was a very ghastly-looking thing," he said.
He added: "It could have done damage to everybody, it's by the good grace it hasn't."
Mr Lawrence, who is a regular attendee at the Oval, said he had "never seen anything like it".
Surrey cricketer Stuart Meaker tweeted: "Well ... we have just officially gone off the field because a metal tipped arrow just landed on the pitch!!"
Well...we have just officially gone off the field because a metal tipped arrow just landed on the pitch!! 👀— Stuart Meaker (@SMeaker18) August 31, 2017
England and Middlesex batsman Nick Compton, who was batting at 28 not out at the time, joked: "Sir Robin of Loxley has just arrived at the Oval."
Sir Robin of Loxley has just arrived at the Oval 👀 #bowandarrow 💪🙏🏻— Nick Compton (@thecompdog) August 31, 2017
Compton and his colleague John Simpson were at the crease as the arrow landed on the field.
The match was stopped after the first ball of the 69th over with Middlesex at 214 for seven in their second innings on the fourth and final day.
A police spokesman added: "At this stage, the incident is not being treated as terrorism-related."
Surrey County Cricket Club chief executive Richard Gould said the motive was unclear and security at the Oval would be reviewed.
He told Sky News: "I have no idea of motive at the moment - we don't know if we were deliberately targeted or whether someone has been irresponsibly firing this thing at something outside the ground and it's just happened to land at the Oval.
"A crossbow bolt threat is not something that has been faced for as long as I can remember.
"We will of course review and see if there are other measures that might be taken into consideration."
Asked whether the barriers in place were sufficient, he replied: "I think you misunderstand the nature of a crossbow bolt in that a crossbow bolt can be fired hundreds of feet into the air and then land in the ground.
"So unless we are going to put up fences that are hundreds of feet high then that's clearly not a practical thing to do.
"It does pose particular difficulties because we cannot build a wall that will prevent such a thing from breaching it."
Mr Gould said the arrow could "definitely" have harmed someone.
He told reporters: "We don't know where it was fired from, so I don't know what kinetic energy it had when it landed.
"If it was fired from close range it certainly could have caused serious damage or fatality.
"If it was fired from a long way away and it was losing kinetic energy, injury would be a lot less likely."