While no information has been released about the nationalities of two suspects in Friday's subway bombing in London, national security advisor H.R. McMaster indicated Sunday that the Trump administration is eager to use the attack to bolster its argument for a ban on travelers from six majority-Muslim countries.

Appearing on ABC's "This Week" Sunday morning, McMaster said the White House is examining "how to protect the American people better, how to ensure that we know who these people are who are moving."

NSA McMaster tells @GStephanopoulos that a new travel ban "is something that we're looking at." #ThisWeek pic.twitter.com/rxisKa68S1 — This Week (@ThisWeekABC) September 17, 2017

His comments came two says after Trump tweeted about imposing a "larger, tougher, and more specific" ban on travelers to the U.S. than the one he proposed in January. Trump made his comments as authorities were investigating Friday morning's attack and was chastised by British officials for the "unhelpful" remarks.

ISIS claimed responsibility for the attack on Friday but no evidence or proof of its connection has been found.

The travel ban has come up against widespread protests as well as legal challenges, with federal courts blocking the executive order and states filing lawsuits. The Supreme Court allowed a suspension of travel from the six countries in question —Syria, Yemen, Libya, Somalia, Iran, and Sudan—for 90 days, making exceptions for certain family members. Last week, the high court ruled that the travel suspension can apply even to refugees who have connections with resettlement agencies in the United States.

The court will hear arguments next month regarding the constitutionality of President Trump's original ban.