President Obama slams 'inexcusable' IRS targeting of conservative groups

US President Barack Obama has condemned the actions of Internal Revenue Service (IRS) staff after it emerged that some conservative groups were singled out for extra scrutiny.

IRS Acting Commissioner Steve Miller was asked by Treasury Secretary Jack Lew to resign over the scandal.

It was revealed earlier in the week that the IRS had used key words such as "Tea Party" and "patriot" to subject applications by conservative groups seeking tax-exempt status to extra scrutiny in the run-up to the 2012 presidential election.