Stephen Bannon, a former banker who runs the influential conservative outlet Breitbart News and is known for his fiercely anti-establishment politics, has been named the Trump campaign's chief executive. Kellyanne Conway, a veteran Republican pollster who has been close to Trump for years, will assume the role of campaign manager.

Two Trump campaign aides confirmed the staff's reshuffle early Wednesday, requesting anonymity to discuss personnel changes without permission.

Trump issued a statement hours later. "I have known Steve and Kellyanne both for many years. They are extremely capable, highly qualified people who love to win and know how to win," he said. "I believe we're adding some of the best talents in politics, with the experience and expertise needed to defeat Hillary Clinton in November and continue to share my message and vision to Make America Great Again."

The campaign played down the notion that Trump was reacting to the polls or saw his bid in crisis.

"These announcements come at a time of significant growth for Mr. Trump's campaign, with the first major TV ad buy of the general election slated to start later this week and with additional top-flight operatives joining the movement on a near-daily basis," the campaign said in the statement.

The Wall Street Journal first reported the moves.