It also comes amid a Fox News report that a Department of Justice official allegedly met with individuals behind the infamous Trump dossier who were working with a firm that employed his wife.
Sekulow was referring to the FBI and DOJ cases, although in the latter, it was unclear if there was any connection to the Mueller investigation.
Though the move could be seen as an attack on Mueller, Trump's attorneys have stressed they have no issues with Mueller, who was an FBI director, is a Republican and was appointed to his current post by a Trump administration official.
In the FBI case, a counterintelligence agent, Peter Strzok, was removed from the Russia probe after the discovery of text messages sent by the agent that were viewed as potentially anti-Trump. Peter Carr, a spokesman for Mueller, has said Strzok was removed from the team "immediately upon learning of the allegations."
Trump seized on the news, saying in a tweet that the FBI's "reputation is in tatters."
During a recent congressional hearing with FBI Director Chris Wray, House Republicans used Strzok's situation to question the integrity of federal investigations, including the probe being led by Mueller.
Strzok has spent much of his law enforcement career working counterintelligence cases, and he has been widely praised by federal law enforcement officials who spoke with ABC News. He reportedly left Mueller’s team in late July and is now working for the FBI's human resources division.
The FBI has declined to comment on Strzok.
In the second case, Fox News reported that the wife of a DOJ official, Bruce Ohr, worked for Fusion GPS, the firm behind the infamous anti-Trump dossier.
According to the report, Ohr met last year with the author of the dossier. The alleged meeting occurred several months before Mueller was appointed special counsel, and it is unclear if Ohr has any connections to the Mueller-led investigation.
Asked why Ohr was meeting with representatives from Fusion GPS, a DOJ official told ABC News, "He's known these guys for a very long time," but didn't specify what the meeting was about. Ohr has been removed from his post in the deputy attorney general's office but remains at the Department of Justice. He has been cleared to testify as requested, per the DOJ.
Sessions told Fox News on Tuesday he has "put a senior attorney, with the resources he may need, to review cases in our office and make a recommendation to me if things aren't being pursued that need to be pursued, if cases may need more resources to complete in a proper manner and to recommend to me if the standards for a special counsel are met, and the recommended one should be established."
The call for a second special counsel is not entirely new.
ABC News' Mike Levine and Katherine Faulders contributed to this report.