The actor joined other celebrities in commenting on the flare-ups of rioting and looting across the country since August 6.
Kumar said on Twitter: "England is now being destroyed by its very own misled youths. The circumstance for which these horrific riots came about is very sad, but this is no way to handle vengeance.
"I really hope everyone back in England keep themselves as well as their families safe. Stay low for a while or if u want fight back, but safely, it is your prerogative after all...."
However, he also posted: "I understand why people are angry but in this day and age how do humans still react the same way cave men once did.
"Good old England, the very country so many rely on, is being battered by its own angered youngsters who have threatened & abused the very city that has taken care of them!"
Kumar recently wrapped up filming the London shoot of the ensemble comedy sequel Housefull 2, co-starring Amitabh Bachchan, John Abraham and Asin Thottumkal.
He recently admitted that he is keen to star in more action films after doing a run of comedies.