President Trump asked legal aides Monday to seek a quick Supreme Court review of what he calls his "travel ban" from six Muslim countries, and suggested he would seek to expand that ban in the wake of the weekend terrorist attack in London.

"The Justice Dept. should ask for an expedited hearing of the watered down Travel Ban before the Supreme Court - & seek much tougher version!" the president tweeted.

He did not specify what a "tougher version" might entail.

In another message, Trump took a swipe at the courts and said the U.S. needs to a better job of screening people coming into the country because of concern about terrorism: "In any event we are EXTREME VETTING people coming into the U.S. in order to help keep our country safe. The courts are slow and political!"

Lower courts have ruled against Trump's proposal to temporarily ban travel from six Muslim majority countries: Iran, Libya, Somalia, Sudan, Syria and Yemen. Some judges cited Trump's own campaign rhetoric -- including calls to block all Muslims from entering the country until terrorist screening procedures could be improved -- in saying the plan improperly targets religion.

While Trump aides once disputed the term "ban," the president has trumpeted the word in the days since the terrorist attack in London. On Monday, the president tweeted: "People, the lawyers and the courts can call it whatever they want, but I am calling it what we need and what it is, a TRAVEL BAN!"

There have been two versions of the travel order. After courts struck down an initial version, aides removed Iraq from the list and made other changes that Trump criticized during the Monday tweet storm.

"The Justice Dept. should have stayed with the original Travel Ban, not the watered down, politically correct version they submitted to S.C.," Trump said.