UPDATE 1-Trump to talk to Democrats again as he presses tax reform

(Adds details on meeting, quotes on lawmakers)

WASHINGTON, Sept 13 (Reuters) - U.S. President Donald Trump was set to host Democratic and Republican House lawmakers at the White House on Wednesday, seeking to build support across the political spectrum for tax reform that he said should include tax cuts for the middle class.

The Republican president, who has shown a new willingness to engage with Democrats in recent days, discussed tax plans over dinner on Tuesday with a small group of Republican and Democratic senators as he tries to push for rapid tax legislation.

Several senators who attended the dinner said in television interviews on Wednesday that Trump had been clear the tax package could not be focused on wealthy Americans.

Republicans control both chambers of Congress and the party's leaders have been trying for most of the year to come up with a detailed tax plan while ignoring the Democrats. Democrats have criticized their effort as aimed mostly at the rich.

"The president stressed that he wants this to be a middle class tax cut," Republican Pat Toomey, one of the senators who attended the Tuesday dinner, told MSNBC.

Democratic Senator Joe Manchin told CBS News that Trump "was adamant this is not a tax cut for the rich" and that the White House was "very aggressive" on the need for a bipartisan plan.

The White House called the dinner "highly productive," saying in a statement it would "spur constructive discussion."

Trump is promoting his goals of a simpler U.S. tax code with lower rates, including on corporate taxes, even as a detailed plan has yet to emerge from either the White House or Congress.

He was due to meet on Wednesday with 13 lawmakers from the House of Representatives, including eight Democrats and five Republicans. House Republican leaders were also expected to give their members an update on the tax reform effort, including a general timeline to pass a bill.

In Twitter posts early on Wednesday, Trump urged lawmakers act quickly.

"The approval process for the biggest Tax Cut & Tax Reform package in the history of our country will soon begin. Move fast Congress!" Trump wrote.

Trump reached a surprising deal last week with Democratic leaders on fiscal issues, blindsiding Republican leaders. That led to a bill that Trump signed on Friday extending the government debt limit for three months and providing about $15 billion in hurricane-related aid. (Reporting by Susan Heavey, Roberta Rampton, David Morgan and Makini Brice; Editing by Frances Kerry)