U.S. President Joe Biden acknowledges reporters and visitors as he departs on travel to Wilmington, Delaware from the South Lawn of the White House in Washington, June 18, 2021.Carlos Barria | ReutersPresident Joe Biden expects to meet with lawmakers this week as a group of Democrats and Republicans try to forge an infrastructure plan that could get through Congress with bipartisan support, White House press secretary Jen Psaki said Monday.At least 21 senators from both parties have backed a framework that seeks to spend roughly $1 trillion on transportation, broadband and water systems. Biden and Democratic congressional leaders have raised questions about how lawmakers plan to pay for the plan, while liberals have called it inadequate to fight climate change.The president’s talks this week could mark a final push to find a compromise before Democrats try to pass a sprawling infrastructure plan on their own. While the discussions between Democrats and Republicans go forward, Biden’s party has started the process of drafting a budget resolution that would allow them to pass a bill without GOP votes.A bipartisan deal could now depend on whether the White House and Republicans can strike a funding compromise, and on what Democratic leaders promise skeptical progressives they can pass as part of a separate bill. Biden will not support a potential increase in gas taxes or vehicle mileage fees — revenue raisers floated as part of the bipartisan talks — because they would break his promise not to hike taxes on people making less than $400,000 per year, Psaki told reporters Monday.”That is a nonstarter for him,” she said.Psaki added that Biden supports boosting IRS enforcement to ensure wealthy people do not avoid existing taxes. Doing so would meet a Republican demand not to revise the 2017 GOP tax cuts, she said.Biden initially called to hike the corporate tax rate to 28% to pay for his $2.3 trillion infrastructure plan.Disagreements over how broad the proposal should be and how to pay for it threaten to trip up the bipartisan plan in the Senate. Sen. Bernie Sanders, a Vermont independent who caucuses with Democrats, said Sunday he would not support a higher gas tax or an electric vehicle mileage fee as part of an infrastructure bill.”One of the concerns that I do have about the bipartisan bill is how they are going to pay for their proposals, and they’re not clear yet,” he told “Meet the Press.” “I don’t know that they even know yet, but some of the speculation is raising a gas tax, which I don’t support, a fee on electric vehicles, privatization of infrastructure. Those are proposals that I would not support.”The bipartisan group could consider excluding a gas tax increase from the plan, Sen. Rob Portman, an Ohio Republican and one of the negotiators, told “Meet the Press” on Sunday. He said the Biden administration “will need to come forward with other ideas without raising taxes.”Meanwhile, Democrats including Sen. Ed Markey of Massachusetts have said they will not back a bill that does not include more funding to combat climate change. On Monday, he told MSNBC that he “cannot support a deal that does not have climate at its center.”Some Democrats have signaled the party could try to pass a broader bill that address climate change without Republicans after Congress approves a bipartisan infrastructure plan. Markey said he would need “an absolute guarantee that climate is dealt with” in a second bill in order to back the bipartisan framework.Eleven Republicans have said they support the plan. In the evenly split Senate, only one Democrat could oppose it for it to win the 60 votes needed to overcome a filibuster.The plan put forward by the Democratic and Republican senators focuses on what the GOP has called physical infrastructure. Biden and his party have pushed to pass policies including care for dependent family members and upgrades to housing and schools as part of their infrastructure plans, contending they are necessary to boost the economy.If Democrats cannot strike a deal with the GOP, they could push ahead with a multitrillion dollar proposal that would not only upgrade transportation, utilities and broadband, but also accelerate the adoption of clean energy, expand child care and boost job training programs. To be successful, all 50 Senate Democrats would have to vote for that bill. At least one Democrat, Sen. Joe Manchin of West Virginia, has insisted on passing an infrastructure bill with Republican votes. It is unclear if he would back a separate reconciliation bill if Congress passes an initial infrastructure plan with bipartisan support.Subscribe to CNBC on YouTube.