With several high-profile terrorist attacks around the world, including Paris and San Bernardino, Calif., many have raised serious concerns about how thoroughly individuals entering the U.S. are screened.

In particular, a lot of focus has been paid to the refugee process. Americans are understandably worried that terrorists might use any and all opportunities to enter the United States.

So what does the refugee vetting process look like?

First, most applicants apply for refuge through the Office of the United Nations High Commissioner for Refugees, or UNHCR. The office then forwards some applications to the U.S. State Department, which prepares these applications for adjudication by Department of Homeland Security's U.S. Citizenship and Immigration Services.

Once an applicant is referred to the State Department, biometric and biographic checks are done against various U.S. security databases at multiple points throughout the process.

Multiple agencies systems and databases are incorporated in this process, including:

The State Department

-Consular Lookout and Support System

-Consular Consolidated Database

-Department of Homeland Security

-TECS (a DHS security system)

-DHS Automated Biometric Identification System

National Counterterrorism Center/FBI's Terrorist Screening Center

-Terrorist Identities Datamart Environment

-Terrorist Screening Database

Federal Bureau of Investigation

-Extracts of the National Crime Information Center's Wanted Persons File, Immigration Violator File, Foreign Fugitive File, Violent Gang and Terrorist Organization File (and the Interstate Identification Index)

-Integrated Automated Fingerprint Identification System / Next Generation Identification

Interpol

Drug Enforcement Administration

Department of Defense

-Automated Biometric Identification System

In addition, the refugee process requires a security advisory opinion to be completed by the FBI and the intelligence community on many refugee applicants who are considered higher risk. Similarly, interagency checks are constantly being done in connection with a wide range of U.S. agencies.

In additional to these background checks, U.S. Citizenship and Immigration Services conducts a refugee interview. These interviews cover everything from refugee and immigration matters to security and country specific questions.

For example, Syrian refugee officers must undergo a one week training course on Syria-specific issues, including classified information. Additional scrutiny is already being applied to Syrians through the enhanced review for Syrian applicants process that puts additional security and intelligence resources at the disposal of adjudicators.

Only at this point can an application be approved. For those that are approved, health screenings and orientations begin. The State Department and Office of Refugee Resettlement within the Department of Health and Human Services work with voluntary resettlement agencies to arrange for resettlement services and assistance.

After an average of 12-18 months, this process ends with entry into the U.S. According to the Department of Homeland Security, of the approximately 23,000 Syrian referrals made by the U.N. High Commissioner on Refugees to the U.S., only about 2,000 have been accepted. The U.S. refugee system can be, should be, and is being picky at who we allow to enter the U.S. as a refugee.

The U.S. has made constant improvements to the program, learning from mistakes such as when in 2009, two Iraqi terrorists were caught in the U.S. after slipping through the vetting process. It is worth noting that these are the only two individuals who slipped through the screening process

Is it enough? Is our government doing adequate due diligence? These are the key questions.

That's why the best recommendation for Congress right now is to demand detailed information from the administration on how risks are being mitigated. The administration should remain selective in the refugees it accepts, focusing on those applicants about whom the U.S. has an acceptable amount of intelligence.

While this process is even more rigorous than most other visa programs, after the attack in San Bernardino, the American people deserve and Congress should request details about how all forms of vetting can be and should be constantly improved. The government owes it to its citizens to use all lawful tools at its disposal to prevent terrorist travel.

Americans deserve a responsible program so they can continue to support refugees while also addressing real security concerns.