WASHINGTON, Nov 22 (Reuters) - Republican Sean Parnell, whom former President Donald Trump endorsed in next year"s toss-up U.S. Senate election in Pennsylvania, said he was suspending his campaign on Monday, local media reported. The decision came after Parnell lost a battle over the custody of his three children amid allegations of physical and verbal abuse of his estranged wife, according to the Philadelphia Inquirer. Parnell, an Army veteran, was attempting to win the seat held by conservative Republican Senator Pat Toomey, who is retiring after next year. The Pennsylvania Senate race is seen as one of the most competitive races in the November 2022 congressional elections and could help determine whether Republicans succeed in their drive to win majority control of the chamber. According to the Philadelphia Inquirer, a judge granted Parnell"s wife primary custody of their children following allegations of past physical abuse and uncontrolled anger. The newspaper quoted Parnell denying the allegations. In May, Parnell announced he would run to replace Toomey. In a video he posted on Twitter, Parnell highlighted his support of gun rights. The Afghanistan war veteran said he wanted to help repair "a generational crisis" created by "crazy liberals." U.S. Representative Conor Lamb, who is in his third term in the House of Representatives, is trying to capture the Democratic nomination for the Senate seat among a crowded field. Reporting by Richard Cowan; Editing by Dan Grebler