US President Donald Trump says he is sceptical a deal can be reached on border security before government funding expires again next month.
Mr Trump spoke to the Wall Street Journal as 800,000 federal employees returned to work after the longest ever closure of federal agencies lasting 35 days.
The Republican president said he doubted he would lower the sum he is prepared to accept to pay for the US-Mexico border wall he promised in his election campaign.
Congress must negotiate a new bill by 15 February to avoid another shutdown after Mr Trump signed a bill on Friday to a temporary halt to the shutdown.
A committee of lawmakers from both parties is poised to negotiate, but Mr Trump said the chances of a political breakthrough were "less than 50-50", the Journal reported.
Asked if would accept less than the $5.7bn he wants to build a border barrier, he said "I doubt it".
"I have to do it right," he said, noting that he has not ruled out a second shutdown to accomplish his signature campaign pledge.
The president also said he doubted he would grant citizenship for immigrants who entered the US as children without documentation, to strike a grand bargain with Democrats.
Mr Trump bowed to mounting pressure on Friday to end the crippling shutdown of about a quarter of the US government.
While Congress quickly passed a bill to fund federal agencies, Mr Trump again came away without a dollar of taxpayers' money for his long-promised border wall.
His perceived retreat provoked a welter of conservative criticism, prompting him unusually to lash out at his favourite outlet, Fox News.
"Never thought I'd say this but I think @johnrobertsFox and @GillianHTurner @FoxNews have even less understanding of the Wall negotiations than the folks at FAKE NEWS CNN & NBC!", Mr Trump tweeted on Sunday.
Never thought I’d say this but I think @johnrobertsFox and @GillianHTurner @FoxNews have even less understanding of the Wall negotiations than the folks at FAKE NEWS CNN & NBC! Look to final results! Don’t know how my poll numbers are so good, especially up 19% with Hispanics?— Donald J. Trump (@realDonaldTrump) January 28, 2019
In a first version of that tweet, the president misspelled the Fox correspondent Gillian Turner's name as Jillian - tagging an unsuspecting California teenager instead.
He also took a dig at right-wing commentator Ann Coulter - who last week labelled him a wimp - telling the Wall Street Journal: "I hear she's become very hostile. Maybe I didn't return her phone call or something."
Meanwhile, as the president rails against illegal immigrants, reports have emerged in recent weeks that his own golf resorts have been hiring undocumented workers for years.
On Saturday, the Associated Press reported that a dozen undocumented immigrants employed at Mr Trump's New York club were abruptly fired.
A lawyer for the employees said managers had been aware of their illegal status for years, but there was a "don't ask, don't tell" attitude among staffers.
Many of those dismissed had worked at the club for over 12 years, and one employee had the keys to the bedroom of Mr Trump's 35-year-old son Eric, according to reports.
Last month, a housekeeper at a Trump club in New Jersey told the New York Times managers knowingly hired undocumented immigrants and sometimes helped get them fake documentation.