Tipster Tyler C. writes that there's a "crazy standoff" going down at Geary & Collins, and witnesses have taken to Twitter to report what they're seeing:

Corner of Geary and Collins something going down lots of cops with automatic rifles pointed up to apartment window pic.twitter.com/de75K5wc8w

— michael fisher (@fishermp) April 10, 2016

#SFPD entering in & out of 205 Collins at Geary pic.twitter.com/t8um1hYBdE

— Nancy Mancias (@nancymancias) April 10, 2016

#SFPD huddled behind parked cars on Collins at Geary in The Richmond pic.twitter.com/lTP3k4m0yw

— Nancy Mancias (@nancymancias) April 10, 2016

Lots of #sfpd on Collins at Geary w/rifles Some seemed to go in w/shields to apt bldg pic.twitter.com/mlegKKkNJB

— Steve Rhodes (@tigerbeat) April 10, 2016

Avoid the area of Collins St. between Geary Blvd. and Anza St., due to #SFPD activity. Thank you.

— San Francisco DEM (@SF_emergency) April 10, 2016

Just took video riding past Geary and Collins. SFPD are in position around the block and armed. pic.twitter.com/scaFqpGc7x

— A Flaming Homosexual (@onebrightlight) April 11, 2016

We've contacted SFPD for details on what might be going on, but for now, avoid the area if you can. 

Update, 4/11: A Reddit thread indicates that the police action was in response to an armed man who may have taken his own life.

If you or someone you know is having suicidal thoughts, visit San Francisco Suicide Prevention, call the crisis line at (415) 781-0500 or text MYLIFE to 741741.