Washington, Jul 30 (IANS): US President Donald Trump has threatened to shut down the government if the Democratic Party does not cooperate on border security issues.

"I would be willing to 'shut down' government if the Democrats do not give us the votes for Border Security, which includes the Wall!

"Must get rid of Lottery, Catch and Release etc. and finally go to system of Immigration based on MERIT! We need great people coming into our Country!" Trump tweeted on Sunday.

The threat came on top of another fiery tweet posted earlier on the same day, which said: "Please understand, there are consequences when people cross our Border illegally, whether they have children or not -- and many are just using children for their own sinister purposes.

"Congress must act on fixing the DUMBEST and WORST immigration laws anywhere in the world! Vote 'R'," referring to Republicans, Xinhua news agency reported.

The tweets were in response to attacks on the US government's family separation policy, which saw thousands of minors separated from their parents who entered the US illegally.

The controversy that ensued the family separation policy caused many Republican lawmakers to distance themselves from Trump's tough immigration agenda.

It also stalled legislative progress in Congress for comprehensive immigration reform, which had been a major promise for his supporters during his 2016 campaign.

However, Trump's menacing tweets were rebuffed even by his own party members, who said "shutting down the government will not be helpful".

Congressman Steve Stivers, a Republican from Ohio, downplayed the possibility of a shutdown in a TV interview on Sunday, saying: "I think we're going to make sure we keep the government open."

The US federal government last shut down was over a spending bill when the Congress failed to reach consensus due to political fights.