405 closed by kids on freeway **

Northbound lanes of the San Diego Freeway have been closed north of Sherman Way because of protesting students on the freeway. The CHP called a Sigalert at 11:53 am, with southbound lanes reopened at 12:17. An emailer monitoring police radios also says that the LAPD has been put on tactical alert across the Valley due to fights in the Van Nuys Civic Center.

Update: Sigalert cancelled at 12:20 and all lanes are now open.

* Tuesday's protests: More than 7,000 Los Angeles Unified students walked out today, the LAT says. 1:20 pm

** About 30 arrested: Handcuffed and lined up against the sound wall, in ABC7's footage. 4:40 pm