Senate Finance ranking member Chuck Grassley (R-Iowa), a key health care negotiator, is encouraging conservative House Democrats to continue opposing Speaker Nancy Pelosi (D-Calif.) and her leadership team’s plans for health care reform.

In a Twitter message posted Friday around midday, Grassley implored the Blue Dog Democrats to stand firm in their opposition, which has delayed movement of health care legislation in the House. Pelosi and House Energy and Commerce Chairman Henry Waxman (D-Calif.) are in negotiations with Blue Dog leaders to resolve their differences.

“PTL BluDogs Keep barkin Pelosie bill is Govt takeovr of healthCare Breaks Obama promise ‘keep what u hv’ Puts Wash Burocrats in chrg MUSTSTOP,— Grassley said in his Twitter post.

On the Senate side, Grassley, Finance Chairman Max Baucus (D-Mont.), and four other Senators — two Democrats and two Republicans — remain locked in bipartisan health care negotiations. The gang of six is not scheduled to meet Friday but is expected to resume its discussions next week. The group hopes to reach a deal in time to mark up a bill before adjourning for the August recess.