A week ahead of the primary election, the two Republican hopefuls for governor have pulled in a pair of high-profile endorsements.

Mitt Romney, the former governor of Massachusetts and 2012 GOP presidential nominee, gave his backing Tuesday to Cranston Mayor Allan Fung via a series of online messages.

Meanwhile, Ken Block on Tuesday received the endorsement of John Robitaille, the 2010 Republican nominee for governor, during an event at the State House.

The GOP side of the governor’s race has garnered less overall attention than the Democratic primary contest. Fung and Block have both raised and spent exponentially less than their Democratic counterparts, and have had a far lesser advertising presence on television.

The contest has been spirited, however, and frequently contentious. The lack of recent polling and the nature of the primary electorate also make the race unpredictable, even to insiders and old political hands.

The announcement of Romney’s endorsement of Fung came through a YouTube video, an email to supporters and a campaign press release sent to the media.

“Allan stood with me, while his opponent, Ken Block, supported Barack Obama,” Romney narrates during the online video, which is titled “Romney for Fung” and features various photos of the two men in a slideshow. “And Allan is a proven leader who will turn around Rhode Island. He’ll challenge the special interests and shake up the State House.”

“I am humbled to receive such enthusiastic support from Governor Romney for my campaign for governor of Rhode Island,” Fung said in the press release. “Governor Romney brought real reform and economic revitalization to Massachusetts and helped to set an example of the type of success that we should strive to achieve for the people of Rhode Island. Throughout my time in public service, I have supported fellow Republican candidates in local, state, and federal elections and I am extremely grateful for the outpouring of support I have received in this campaign.”

Fung has, throughout the campaign, questioned Block’s Republican and conservative bona fides, frequently pointing out that the Barrington businessman has acknowledged twice voting for Obama and initially supporting the federal health care reform law. The mayor has also touted his record in Cranston, framing himself as a reformer with a record of results.

Block has countered by questioning Fung’s record, with particularly pointed criticism of the mayor’s handling of the Cranston Police Department in light of the controversies that have surrounded it in recent months. A businessman and Barrington resident, Block has sought to position himself as a political outsider who will focus almost exclusively on fostering economic growth and reforming the state’s political culture.

Fung has also said Block, who ran as the Moderate Party’s nominee in 2010, took votes from Robitaille in a close election that saw Lincoln Chafee win the governorship.

In a press release announcing his endorsement, Robitaille said Block has a “clear understanding” of the issues facing the state and a “credible plan to improve how the state operates.”

“Ken’s experience as a job creator and problem solver has served him well in the private sector,” Robitaille states in the release. “This same experience is what we need in a governor to tackle the enormous budget, operational and service issues we face in these difficult economic times.”

“I am thrilled to have the endorsement from John Robitaille, a strong conservative and a recognized leader within our Republican Party,” Block said in the release. “I have gotten to know John on a personal level and deeply respect his commitment to our state. He and I share the same vision of ensuring a better future for our children and grandchildren here in Rhode Island.”

It was also reported Tuesday that state Rep. Brian Newberry of Smithfield, who serves as the House minority leader, planned to switch his endorsement in the GOP race from Fung to Block.

Fung on Tuesday held an event with former Gov. Lincoln Almond. The men toured VR Industries on Strawberry Field Road in Warwick.

Fung and Block were set to square off Tuesday night in a televised debate at the Providence Performing Arts Center. The debate was co-sponsored by WPRI and the Providence Journal.

The primary election will be held Sept. 9.