How to create a multi-table inter joined update query?

I have essentially the following query that requires an update query written.  This update query

would update TAB_A(s) COL1 & COL2 with values from TAB_B and TAB_C as follows:

SET :

TAB_A.COL1 = TAB_B.COL1

            TAB_A.COL2 = TAB_C.COL2

 

SELECT     TAB_A.COL1,     TAB_A.COL2 FROM     TAB_A,     TAB_B,     TAB_C  WHERE (         (TAB_C.COL3 = TAB_B.COL3)         AND (TAB_B.COL1= TAB_A.COL1)        )

 

How would an update query be constructed based on the above information?

Joins are important.