President Trump backed two successful U.S. Senate nominees in Pennsylvania and Nebraska, which were among the four states holding primaries Tuesday.

Two of the president’s favored candidates, Lou Barletta in Pennsylvania and Deb Fischer in Nebraska, won their U.S. Senate primaries.

Barletta, currently a congressman, beat state Rep. Jim Christiana to become the Republican challenger for Democratic Sen. Bob Casey, who is seeking a third term in November.

Barletta was a Trump supporter before the 2016 presidential nomination was settled. Trump asked Barletta to run for Senate, and the president is expected to visit Pennsylvania to campaign for him. The president also recorded telephone calls last weekend backing Barletta “fully, strongly and proudly.”

Fischer, the incumbent, defeated four GOP challengers and will be the strong favorite to win re-election in deep-red Nebraska. Her Democratic opponent is Lincoln City Councilwoman Jane Raybould.

Early Tuesday afternoon, Trump tweeted: “Nebraska – make sure you get out to the polls and VOTE for Deb Fischer today!”

Democrats have viewed Pennsylvania has a key battleground state to winning back control of Congress. In the House race, six women -- 5 Democrats and 1 Republican -- won the nominations. The nominees are poised to break the all-male hold on the 18-member U.S. House delegation.

Chrissy Houlahan, an Air Force veteran, is the uncontested Democratic nominee for another suburban Philadelphia seat where she's heavily favored in November. Houlahan will face Republican nominee Greg McCauley, a tax attorney, in November.

Women won contested Democratic primaries in three other seats in Pennsylvania, although two of those seats are in solidly Republican districts and another is considered a toss-up in November, The Philadelphia Inquirer reported.

Jess King of Lancaster County scored the Democratic nomination without opposition. Susan Wild, representing a district north of Philadelphia, won the nomination, beating both District Attorney John Morganelli and Pastor Greg Edwards.

Pearl Kim, the lone female Republican candidate, won the GOP nomination in a district south of Philadelphia.

The Associated Press contributed to this report.