How to convert specific time format to timestamp in R?

How to convert specific time format to timestamp in R?

I am working on "Localization Data for Person Activity Data Set" dataset
from UCI and in this data set there is a column of date and time(both in
one column) with following format:
27.05.2009 14:03:25:777
27.05.2009 14:03:25:183
27.05.2009 14:03:25:210
27.05.2009 14:03:25:237
...
I am wondering if there is anyway to convert this column to timestamp
using R.