"HillaryClinton can illegally get the questions to the Debate & delete 33,000 emails but my son Don is being scorned by the Fake News Media?", he tweeted on Sunday.
The comments come as congressional committees and the Federal Bureau of Investigation continue to investigate Russian efforts to influence the 2016 presidential election - and whether members of Trump's campaign cooperated.
Political opponents see the email revelations as the most concrete evidence of collusion between the Trump campaign and Russian Federation during the election.
The information had been described as "part of Russian Federation and its government's support for Mr. Trump".
Mr Sekulow appeared on five television networks on Sunday to defend Mr Trump and his son, following the latest accusations of collusion between the Trump campaign and Russian Federation.
Rather than call the authorities - as campaigns have done before in such situations, and as is required by patriotism and, perhaps, the law - they eagerly set up a meeting. He said the president did not attend the meeting in NY and was not aware of it.
Trump 2020 campaign committees have spent almost $700,000 on legal fees between the beginning of April and the end of June, according to the FEC reports.
When first confronted by The New York Times about the meeting with the Russian lawyer, he said it was only about the adoption by Americans of Russian babies. "If that information was then passed to Trump Senior, which the timing of his draft speech indicates, then there's strong evidence that Senior was also in the know". Then, he conceded it was about information that may be helpful to the campaign, but that he wasn't told who the meeting would be with.
The number of people known to have been at the meeting also changed over time.
Later reports revealed that lobbyist Rinat Akhmetshin, who was once a Soviet counter-intelligence officer, also attended the Trump Tower gathering. "Thank you to all of the supporters, who far out-numbered the protesters, yesterday at the Women's US Open", Trump wrote.
On Sunday, the top Democrats investigating Russian meddling in the 2016 election said that e-mails that Trump Jr. sent about the meeting with the Russian lawyer appeared to confirm that members of the Trump campaign had meant to cooperate with Russian officials.
Though, it is still unclear whether Veselnitskaya actually fulfilled the promised compromising information about Clinton or not. He emerged to say that he had witnessed no collusion between the campaign and Russian Federation. "We can't be aware of all the meetings Russian lawyers have overseas", said spokesman Dmitry Peskov.
The poll brought another broadside from Trump.