append df/multiple rows several times in specific place (after each distinct row in a DF/after every 3 rows)

I have a data frame include whole country summary stats "countrylevel"
I have another data frame includes summary stats for each city in the country "citylevel" . (each city has 3 rows 5 columns)

#countrylevel
Id     v1  v2   v3
AC     2.2 3.6  9.2
AR     4.2 5.2  7.1
AW     4.2 5.2  7.1
#citylevel
city area   v1  v2   v3
A       er  2.2 3.6  9.2
A       ea  4.2 5.2  7.1
A       ew  4.2 5.2  7.1
B       er  6.2 7.1  9.2
B       ea  2.5 8.1  5.4
B       ew  7.5 3.8  7.3
C       er  1.5 2.2  3.1
C       ea  1.8 2.3  4.7
C       ew  2.5 9.8  3.8

My question: How can I add "the countrylevel df" after each city in the citylevel df (after every 3 rows)?