** Securitas SECUb.ST falls 6.2% to a three-week low of SEK 139.85; set for its steepest intraday pct drop since November 7, 2023
** Swedish security firm posts Q1 core profit, revenue below estimate
** Q1 EBITA of 2.53 bln Swedish crowns ($259.2 mln) misses analysts' forecast of SEK 2.36 bln in a company-provided consensus
** J.P. Morgan says worse-than-anticipated currency headwinds dragging on co's Q1 results
** Notes sell-side estimates still need to catch up to foreign exchange impact
** Jefferies says co's earnings miss driven mainly by worse-than-expected currency effects, continued weakness in its Critical Infrastructure unit
** Stock among worst performers on pan-European 600 index .STOXX
(Reporting by Jesus Calero and Agnieszka Olenska)
((Jesus.calero@thomsonreuters.com))