Prominent veterans groups are scolding a Republican senator for taking what they say was a cheap political shot at them for not embracing his call for Veterans Affairs Secretary Eric Shinseki to resign.

The dust-up involves North Carolina Sen. Richard Burr, the senior Republican on the Senate Veterans Affairs Committee, at a time when the Obama administration is reeling over allegations about treatment delays and secret waiting lists at VA hospitals and clinics.

Burr said in an "open letter" timed for Memorial Day that the Veterans of Foreign Wars and other groups are "more interested in defending the status quo within VA" than improving care for veterans.

The VFW called Burr's comment "a monumental cheap shot."

Burr is among the lawmakers from both parties who say Shinseki should resign.