Several senators on both sides of the aisle rushed to back Attorney General Jeff Sessions Thursday as he sought to blunt resignation calls from senior Democrats, following revelations he met last year with Russia's ambassador – a detail omitted from recent congressional testimony.

His defenders say such meetings between senators and diplomats were routine. And Sessions even got an inadvertent boost from Democratic Missouri Sen. Claire McCaskill, who in demanding the AG's resignation initially claimed she never called or met with Russia's ambassador -- only for tweets to surface indicating she had, at least twice.

Other former colleagues intentionally came to Sessions' defense, backing the former Alabama senator's claim he only met with Russian Ambassador Sergey Kislyak in his official capacity as a member of the Senate Armed Services Committee.

“I’ve met with the Russian ambassador with a group, in my capacity, with a group of other senators,” Sen. Joe Manchin, D-W.Va., told CNN. “That’s in my official capacity. That’s nothing. That’s my job.”

Sen. Roy Blunt, R-Mo., said in a statement that he’d talked to “at least twenty ambassadors in the last six weeks.”

“It would have been very normal for Sessions, as a senator, to have talked to the Russian ambassador without discussing the election,” Blunt said.

Sen. Ted Cruz, R-Texas, said on MSNBC that he’d met with “six ambassadors in the last five months.” Though he hadn’t met with Kislyak, Cruz said he would do so without reservations.

The statements of support came as other lawmakers -- including the two top-ranking Democrats, Rep. Nancy Pelosi and Sen. Chuck Schumer -- demanded Sessions' resignation.

The calls came in the wake of The Washington Post first reporting that Sessions met with Kislyak in July and September, despite testimony during his confirmation hearing that he had never spoken with Russian officials during the time he was a campaign surrogate for then-GOP presidential candidate Donald Trump.

Sessions is maintaining he never discussed campaign matters with the Russian ambassador, and the White House has backed him.

Sessions, while an Alabama senator, in fact met often with ambassadors from a variety of countries, according to a schedule provided to Fox News by a Department of Justice spokesperson. From April 14 through Nov. 11, Sessions had 30 meetings with ambassadors, including four with the ambassador for Great Britain. The day before then-Sen. Sessions met with Kislyak on Sept. 8, he took a meeting with Ukraine Ambassador Valeriy Chaly. Though it’s unclear what was discussed, the back-to-back meetings occurred a week before Russia accepted a unilateral ceasefire plan in Ukraine on behalf of the separatist rebels it backs there.

Seeking to drive a stake into Sessions’ defense, however, McCaskill tweeted Thursday she had “been on the Armed Services Com for 10 years. No call or meeting w/Russian ambassador. Ever. Ambassadors call members of Foreign Rel Com.”

Except, that’s not quite true.

In a pair of tweets first unearthed by National Review’s Charles C.W. Cooke, McCaskill twice wrote messages about meetings with Kislyak, in 2013 and 2015.

“Off to meeting w/Russian Ambassador. Upset about the arbitrary/cruel decision to end all U.S. adoptions, even those in process,” McCaskill tweeted on Jan. 30, 2013.

On Aug. 6, 2015, McCaskill wrote: “Today calls with British, Russian, and German ambassadors re: Iran deal. #doingmyhomework.”

Today calls with British, Russian, and German Ambassadors re: Iran deal. #doingmyhomework — Claire McCaskill (@clairecmc) August 6, 2015

McCaskill later blamed Twitter's character limit for the seeming disparity in her tweets, suggesting the limit prevented her from being more specific in Thursday's tweet. She downplayed the significance of her own conversations with Russia's ambassador.