how i can merge two file with more than one condition in R?

 file1:
 col1     col2    col3    col4      col5    col6

  1       1355    1355    83.33      10      2
  1       1357    1357     70        12      4
  ...

 file2:
 col1    col2   col3   col4    col5     col6    col7 
 1       1355    +       5       0       GG      GGA
 ...

i want to merge two file if col1 and col2 in two file was the same:
  output:
all columns of file 1 and col3, col6 and col7 from file 2:

 col1     col2    col3    col4      col5    col6    col 7 col8 col9 

  1       1355    1355    83.33      10      2       +     GG   GGA

 ```