Police today issued a community alert warning of "an increase in robbery-related incidents" in June in the Loop area.



The alert lists four attacks in the Central District, saying the victims were approached from behind while walking on the sidewalk and their property taken by force.



Various descriptions have been given for the attackers, but all have been males in their late teens or early 20s, police said.



According to the alert, the attacks happed at:

-- 42 E. Adams on June 20 at 1:50 a.m.

-- 71 W. Van Buren on June 21 at 1:15 a.m.

-- 180 N. Wabash on June 26 at 11:40 p.m.

-- 160 N. Wells on June 30 at 12:43 a.m.



Anyone with information is asked to call Area Central detectives at 312-747-8382.



In a more recent downtown attack, Chicago police arrested 11 young people about 11:20 p.m. Wednesday after one of them beat a man on the 700 block of North Dearborn Street as the others "egged" him on, authorities said.



Police did not speculate if any of the attacks were directly related.