President Donald Trump has blamed opposition lawmakers from the Democratic Party for the deaths of two Guatemalan children in US custody this month.

“Any deaths of children or others at the Border are strictly the fault of the Democrats and their pathetic immigration policies that allow people to make the long trek thinking they can enter our country illegally. They can’t. If we had a Wall, they wouldn’t even try!” Trump said in a tweet.

Felipe Gomez Alonso, 8, and Jakelin Call Maquin, 7, died while in US Border Patrol custody earlier this month after they crossed from Mexico into the US with their fathers.

The tweet came as Trump said he was waiting for Democrats to come back to negotiate a deal to end a week-long partial government shutdown that will almost certainly extend into the new year.

In a tweet on Saturday, Trump said he was “in the White House waiting for the Democrats to come on over and make a deal on Border Security”.

Trump is demanding billions for a border wall between the US and Mexico, which Democrats have refused to provide.

Cooped up in the White House after cancelling his planned vacation to his private Florida club over the impasse,Trump has been firing off Twitter taunts after his surprise visit to US troops in Iraq.

…children in question were very sick before they were given over to Border Patrol. The father of the young girl said it was not their fault, he hadn’t given her water in days. Border Patrol needs the Wall and it will all end. They are working so hard & getting so little credit!

— Donald J. Trump (@realDonaldTrump) December 29, 2018

His aides are claiming that Democrats have walked away from the negotiating table, though Democrats say the White House has not reached out in weeks directly to Democratic House leader Nancy Pelosi.

Trump upped the brinkmanship by threatening anew to close the border with Mexico to press congress to cave to his demand for money to pay for a wall.

Democrats vowed to pass legislation restoring the government as soon as they take control of the House on Thursday but that won’t accomplish anything unless Trump and the Republican-controlled Senate go along with it.

The President did leave the White House on Friday night to join the three men at the centre of the negotiations, Vice-President Mike Pence, Trump’s senior adviser and son-in-law Jared Kushner, and acting chief of staff Mick Mulvaney, for dinner at Pence’s residence at the Naval Observatory.

The effects to the public of the impasse grew as the Environmental Protection Agency, which had the money to function a week longer than some agencies, implemented its shutdown plan at midnight on Friday night.

EPA spokeswoman Molly Block said many of the agency’s 14,000 employees were being furloughed, while disaster-response teams and certain other employees deemed essential would stay on the job.

Trump vowed to ‘drain the swamp’, but what Washington needs right now is someone to empty its rubbish bins. Photo: AP/Jacquelyn Martin

The Smithsonian Institution said its museums and galleries popular with visitors and locals in the capital will close starting midweek if the partial shutdown drags on.

Members of the US Coast Guard will receive their final pay cheques of the year on Monday, the service said in a statement on its website on Friday, after previously warning that payments would be delayed due to the shutdown.

That pay cheque will be their last until the government reopens.

-AAP