Are payroll withholding taxes an expense or a liability?

that depend on who will pay the tax 

if its deducted from the employees then it's a liability

if its the company to pay tax and the employees  received there salary as it is then it's an expense  

It will be an expense as part of salaries and wages and will be a liability until it is paid to the tax authority.

Payroll taxes withheld from employees' are liabilities of the employer. 

I think after all it is just taxes , therefore it is expenses.