Python equivalent R code - numeric seconds from epoch to POSIXlt

Python equivalent R code - numeric seconds from epoch to POSIXlt

I have number of seconds elapsed since an epoch and can convert it to
localtime in python, like so
time.strftime("%Y-%m-%d %H:%M:%S", time.localtime(1378182603));
## yields '2013-09-03 10:00:03'
How can I achieve the same in R?