Former U.S. House speaker Newt Gingrich has officially suspended his bid for the Republican presidential nomination, after winning just two state primaries and amassing more than $4.3 million in campaign debt.

Gingrich made his announcement Wednesday outside Washington, telling supporters this has been “an amazing year” for him, his wife Callista and family. Gingrich also thanked the more than 179,000 donors who he said helped make his campaign possible.

Gingrich emerged as a strong contender after winning the South Carolina primary in January, but his campaign faltered after he lost the following primary in Florida. His only other primary election win came in March in his home state of Georgia. Last week, Gingrich lost contests in five states.

Gingrich has said he plans on helping Republicans seize control of the Senate while maintaining their majority in the House of Representatives. He masterminded the Republican takeover of the House in 1994.

Gingrich's withdrawal leaves former Massachusetts governor Mitt Romney and Texas Representative Ron Paul in the Republican race, but Paul is too far behind Romney, the presumptive nominee, in the delegate count to win the nomination.

Gingrich, who was often critical of Romney during the nomination race, said Romney was by far a preferable alternative to Democratic President Barack Obama, who is seeking a second term in the November election.

Also Wednesday, Romney released a statement saying Gingrich brought creativity and intellectual vitality to American political life. Romney also said during the course of the campaign, Gingrich demonstrated both eloquence and fearlessness in advancing conservative ideas.