Sqldf LIKE operator for Cyrillic words

Question

I have a table - data.frame in UTF-8:

id|city
 1|Moscow
 2|London
 3|

Line 3 is the Russian name of the city. I use the library sqldf:

sqldf("select * from table_name where city like '%Moscow%'") 

In order (returns 1st row)

sqldf("select * from table_name where city like '%%'") 

It returns 0 rows. Why? How to solve this problem?