The White House announced on Thursday that it won't call for the suspension of the fiancée or K-1 U.S. visa that was used by the female shooter in the San Bernardino massacre to gain U.S. entry.

White House Press Secretary Josh Earnest said the suspension "is something that is under careful review" by the Obama administration, according to the Washington Times.

He said if the U.S. State Department and the Department of Homeland Security recommend changes to the K-1 visa programme, President Barack Obama "won't hesitate to order those reforms."

"There is more information that needs to be collected in the context of the investigation to make sure we sort of have a complete picture of what exactly happened," he said.

Tashfeen Malik came to the U.S. from Pakistan as a fiancée of Syed Rizwan Farook. The two were shot dead by the police during the San Bernardino shooting.

"Someone entered the United States through a K-1 visa programme and proceeded to carry out an act of terrorism on American soil. That programme is, at a minimum, worth a very close look," Earnest said.

The U.S. House of Representatives passed a bill Tuesday to change the Visa Waiver Programme that now requires anyone who traveled to Syria, Iraq or Sudan in the last five years to get a U.S. visa.

Lawmakers are reluctant to change the K-1 visa programme including some Republicans who don't want to take any steps to discourage marriage, Politico reported.

Former Homeland Security Department official Matt Mayer said going to the Middle East from Europe and back again without undergoing security checks "has never been easier."

"ISIS today is likely working hard to identify a group of Europeans who can reach America with only a perfunctory security check to launch an attack," Mayer wrote in The Wall Street Journal. "That cannot be allowed to happen."

FBI Director James B. Comey told Congress this week that Farook and Malik started planning to carry out an attack before they were even engaged or before he brought her to the U.S. in July 2014. He said as far as two years ago, the two were already communicating on plans to launch a terrorist attack.

Malik gave a fake address on her K-1 visa application, which investigators said might have been done to evade inquiries into her family's alleged ties to Islamist militants.

"Our government apparently didn't catch the false address in Pakistan she listed on her application or other possible signs that she was radicalised or an operative," said Republican Sen. Chuck Grassley, who headed the hearing Wednesday.