Park rangers at Eastbrookend Country Park in Dagenham called police after seeing a man with a crossbow at around 9.30am on Thursday morning.
Council officials said their description led to a quick arrest a short time later at Dagenham East station where a man was allegedly found with a loaded crossbow and a knife.
Rangers also found two crossbow bolts after searching the park’s woods, which they handed to police.
Barking and Dagenham Council leader Darren Rodwell said similar incidents have been reported in the park since last year.
“I would like to commend the quick thinking of our Community Rangers in spotting the man and getting the police involved,” he said.
“I’m aware this has been happening for a short while and residents have been reporting similar incidents since last year, so I would also like to say a thank you to them for being so vigilant.
“Thankfully there was no harm to any member of the public and hopefully this is now the end of such incidents.”
A Met Police spokesperson said they stopped a man nearby to the park after being called at 9.35am.
The man was arrested on suspicion of possession of an offensive weapon.
The spokesperson confirmed there were no reports of any injuries.
