(CNN) -- Either Mitt Romney got really popular last weekend, or something funky was going on with his Twitter feed.
The Republican presidential nominee's account on the site, which had been gaining followers at a clip of about 3,000 to 4,000 a day, appears to have gained more than 116,000 followers Friday and another 24,000 on Saturday.
That's according to Twitter Counter, an online tool that charts the number of followers that Twitter accounts have over time. Other tools show slightly different numbers and space the gains out differently over a three-day period.
The spike was noticed by Zach Green, who runs 140elect.com, which monitors social-media activity in politics. He charted the growth as 23,926 new followers on Friday, 93,054 on Saturday and 25,432 more on Sunday.
With political campaigns increasingly using social media as a tool to communicate with supporters, a strong presence on sites like Facebook and Twitter is regarded as a measure of relevance. As such, some politicians have been accused of using tricks to artificially inflate their online presence.
For example, Romney's opponent in the primaries, former House Speaker Newt Gingrich, was dinged by a report that as few as 8% of his 1.3 million Twitter followers were real. The rest were drummed up by a program that creates fake accounts to swell someone's follower ranks, the report said. (The campaign denied it.)
Romney had about 807,000 followers Tuesday morning, up from about 670,000 four days ago.
The Romney campaign says it had nothing to do with the spike in the former Massachusetts governor's follower list.
"We have reached out to Twitter to find out additional information regarding the rapid growth," campaign spokesman Zac Moffat told BuzzFeed. The campaign did not immediately respond to CNN's message seeking comment for this story.
Green told Mashable, a CNN content partner, that someone else may have added fake followers in an effort to embarrass the Romney campaign.
He said the new followers don't appear to come from any legitimate increase in popularity. Green's analytics didn't show any increase in Twitter mentions, retweets or other signs that typically would accompany organic growth on the site, he said.
Several online services offer clients the chance to "buy" Twitter followers, although their sites are vague about where the followers come from or how they are acquired. One such service, BuyTwitterFollow, promises to supply 25,000 new followers for a fee of $225.
Even with the bump, Romney remains far behind President Barack Obama on Twitter. Obama has about 17.8 million Twitter followers -- and, it should be noted, the built-in advantage of having been president of the United States for the past 3½ years.