What's the difference between an abstract class and an interface?

Suppose we have two methods M1() and M2() in an interface. An abstract class also has just the same two abstract methods. If any class implemented this interface or inherited from the abstract class, it will have to implement both the methods in it.

So to me, it seems that an interface or an abstract class behaves the same for my scenario. So, can anyone highlight the difference between these two in this specific case and suggest whether to use an abstract class or an interface here?