President Trump will meet with the chairmen of the House and Senate Agriculture committees on Thursday and is expected to insist that the final farm bill include tighter work requirements for food stamp recipients, according to a source familiar with the meeting plans.

The source said the president's “leaning in” on the issue is primarily aimed at putting pressure on vulnerable Democratic senators such as Heidi Heitkamp of North Dakota and Joe Donnelly of Indiana whom Republicans hope to defeat in November.

Ahead of the meeting on Thursday, Agriculture Secretary Sonny Perdue said the president wouldn't issue a veto threat but would tell the lawmakers he "looks forward to some form of work requirements in the farm bill."

He added, "We know from president’s campaign and from his remarks that what he believes is that the believes the American generosity and  and compassion of American people and the American taxpayer should not be abused with a permanent entitlement program which was designed to be a transitional program back back to restore people to independence."

House Agriculture Chairman Mike Conaway, R-Texas, declined Wednesday afternoon to say what he expected from Trump but said a veto threat could help win over some House conservatives.

“The president’s full-throated support for work requirements would be a huge help to some of our folks who are conflicted by wanting to do what we are trying to do on the SNAP program but have some lingering anxieties over the non-SNAP portions of the farm bill,” Conaway said.

The White House congressional liaison, Marc Short, told reporters in response to a Wall Street Journal story that it was “way too early” to talk about a veto threat. But he said that SNAP work requirements were a priority for the president “and that is something he will be encouraging." He said Thursday’s meeting was intended to brief the president on the progress being made on the bill.

Conaway said he still expected the House to debate his committee’s bill next week. The bill would require adults under 60 and parents of children over 6 who receive SNAP benefits to work at least 20 hours a week. Under current law, the work requirement is limited to able-bodied adults without dependents under the age of 50.

The bill also would prevent states from using a procedure called “broad-based categorical eligibility” to allow people to qualify for SNAP if their income exceeds the federal cut-off, which is 130 percent of the federal poverty level. For a three-person household that federal eligibility limit works out to $2,213 a month, or about $26,600 a year. In some states, people can qualify for SNAP with incomes at twice the poverty level.

A veto threat could complicate work on the farm bill for Senate Agriculture Chairman Pat Roberts, R-Kan. He and the committee’s ranking Democrat, Debbie Stabenow of Michigan, have said they are committed to writing a bipartisan bill that would exclude the controversial SNAP provisions in the House bill. The bill would need at least 60 votes to pass the Senate and there are only 51 Republicans.

Roberts told reporters he didn’t expect Trump to make a veto threat on Thursday. ”We have not heard any report or any comment from anybody we’re dealing with in the White House” about that, he said. “Farmers need certainty and predictability and they need a bill,” he said.

Even if the Senate omits the work requirements in its bill, Conaway has said he would insist that a House-Senate conference agreement on the final version include some reforms. Roberts said he incorrectly told reporters Tuesday that the White House meeting was scheduled for Wednesday. It is expected to include Agriculture Secretary Sonny Perdue.

(Updates with Perdue comment Thursday.)