US appeals court upholds block on Trump travel ban

A US appeals court left a block on President Donald Trump's travel ban targeting citizens from six Muslim majority nations in place on Monday - the latest in a string of judicial blows for the controversial measure. 

In its ruling the US Court of Appeals for the Ninth Circuit largely upheld an injunction on the ban issued by a lower court, but said the government was within its right to review the vetting process for people entering the country.

"Immigration, even for the president, is not a one-person show," the three justices said in their unanimous ruling.

"The president, in issuing the executive order, exceeded the scope of the authority delegated to him by Congress."

The decision came just ahead of a deadline for states challenging the ban to submit briefings before the US Supreme Court in response to the Trump administration's request that the nine justices hear the case.

The US Justice Department filed an emergency application to the Supreme Court on June 1, urging it to undo two lower court rulings blocking Trump's decision to prevent entry to travellers from Iran, Libya, Somalia, Sudan, Syria and Yemen for 90 days.

Trump's executive order also temporarily puts a halt to America's refugee programme and reduces the number of refugees to be admitted this year to 50,000, instead of the 110,000 planned by the Obama administration.

The Trump administration argues the measures are needed to ward off terrorist attacks in the country while the government reviews its vetting process.

Critics say the ban is discriminatory and violates the US constitution by specifically targeting Muslim-majority countries.

The Justice Department declined to comment on the latest ruling.