Mr Trump accused The Post of filing incorrect stories.
"Is fake news Washington Post being used as a lobbyist weapon against Congress to keep politicians from looking into Amazon no-tax monopoly?" he said in a series of tweets late last night.
"So many stories about me in the @washingtonpost are Fake News. They are as bad as ratings challenged @CNN. Lobbyist for Amazon and taxes?" Donald Trump said.
"The Amazon Washington Post fabricated the facts on my ending massive, dangerous and wasteful payments to Syrian rebels fighting Assad," he said as he challenged the Post for writing a story on Syria, which he said is wrong.
In a lead story, the Post said that cooperation with Russia is becoming a central part of the Trump administration's counter-ISIS strategy in Syria.
US military planners are counting on Moscow to try to prevent Syrian government forces and their allies on the ground from interfering in coalition-backed operations against the terrorists, the daily said.
Senator John McCain, Chairman of the Senate Armed Services Committee, alleged that by doing so the Trump administration is playing into the hands of the Russian President Vladimir Putin.
In an editorial, The Wall Street Journal wrote that the Trump administration seems to want to find some agreement with Russia to stabilise Syria even if that means entrenching Assad and the Russian and Iranian military presence.
The White House, meanwhile, reiterated its support to the Russia sanctions bill.
"The president has been very vocal about his support for continued sanctions on those three countries. He has no intention of getting rid of them, but he wants to make sure we get the best deal for the American people possible. Congress doesn't have the best record on that," said White House Press Secretary Sarah sanders.