Police are searching an area of Bartlett Park along the Limehouse Cut after getting a 999 call about a stabbing.
Officers are combing the area but have found nothing so far.
"We're searching just in case someone's lying injured," a Scotland Yard spokesman told the East London Advertiser.
"We were called by a member of the public at 3.47pm and will continue searching to make sure."
Police were called initially to Linfield Street, off Poplar's Upper North Street, then switched the search to the park itself on the south side of the canal.
They said there was "nothing to suggest armed officers have been involved in the search" despite reports. A cordon has been set up in part of the park near the canal towpath while the search continues.
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