WASHINGTON — Republicans in the US Congress attacked each other on Tuesday over their leadership's “fiscal cliff” offer to Democratic President Barack Obama as a group of governors visited the White House to voice concern about the impact on the states of the year-end tax-and-spending deadline. The disarray in Republican ranks over how far to compromise the party's anti-tax stance could complicate what are expected to be intense negotiations between House Speaker John Boehner and Obama. Each will need the backing of their respective troops in Congress in order to bargain credibly. The fiscal cliff refers to steep tax increases and deep automatic spending cuts slated to start to take effect on New Year's Day. If Congress and Obama do not act to stop them, economists have warned the US economy could be thrown back into recession. The disagreements among Republicans surfaced as negotiations on a deficit reduction plan designed to supplant and avert the automatic cuts and tax hikes got more serious, with both parties having presented opening offers. Senator Jim DeMint, a South Carolinian with a following among small-government conservatives, lashed out at an offer sent on Monday to Obama by Boehner, a fellow Republican. “Speaker Boehner's $800 billion tax hike will destroy American jobs and allow politicians in Washington to spend even more,” DeMint said in a statement. In the House of Representatives, two first-term Republican Tea Party stalwarts - Tim Huelskamp of Kansas and Justin Amash of Michigan - were removed by party leadership from the powerful budget committee in what Huelskamp called “a vindictive move.” The Republican leadership offered no immediate explanation for the unusual action, but Boehner has had problems bringing in line the large Tea Party wing in the House. Elected to Congress in force in 2010, they regard the speaker as too much of a compromiser and tied his hands during talks in 2011 on raising the debt ceiling. “The GOP leadership might think they have silenced conservatives, but removing me and others from key committees only confirms our conservative convictions,” said Huelskamp. Washington interest groups are now fully consumed by the cliff, and some are in a bit of a panic about what the talks might bring. Tensions erupted on Tuesday at a forum convened by a fiscal responsibility group called Fix the Debt, which seeks to reduce the federal government's debt and includes a range of business, think tank and political leaders. Audience members stood and repeatedly interrupted Republican Senator Rob Portman of Ohio as he attempted to make a speech. They urged protections from cuts for the Social Security and Medicare social safety net programs. Others shouted down the protesters until they marched out of the forum, where Democratic Senate Finance Committee Chairman Max Baucus also made remarks. US stock markets opened slightly higher, with the benchmark Dow Jones industrial average up less than 1 percent after weeks of gyrations tied to the debate on Capitol Hill. — Reuters