Over the weekend, U.S. Immigration and Customs Enforcement officials knocked on the doors of a handful of Los Angeles-area homes. And last month, U.S. Border Patrol agents conducted a three-day raid in rural parts of Kern County targeting Latino farmworkers and day laborers soliciting work in the parking lots of big-box stores.

These actions serve as a reminder that ICE and other immigration officials can show up with little or no warning at homes, businesses or in public places.

And given the Trump administration’s stated desire to ratchet up immigration enforcement and deportations, advocacy groups for workplace and immigrant rights say it’s vital for business owners to prepare themselves and their employees for any potential visits from ICE.

“The best way to counteract feeling overwhelmed is to be prepared,” said Giuliana Gabriel, vice president of human resources at the California Employers Assn.

Among the reasons immigration authorities may visit a workplace include a Form I-9 audit, a raid, or to detain a specific person. Employers might be notified of a visit, or it could happen without warning.

Having such officials at a work site can feel overwhelming because employees might be “unsure of their rights, the purpose of the search, or what might happen next,” Gabriel said.

Employers, she added, should consider creating a response plan for their managers to follow in the event of an ICE visit.

“Some employers may choose to conduct ‘ICE Drills’ — similar to fire drills — for staff to gauge preparedness and help employees keep calm in the event of a real visit,” she said.

Federal law requires every employee on a payroll to have a Form I-9 on file. Those documents prove an employee is authorized to work in the U.S., according to the California Employers Assn.

To comply with the law:

“We recommend having strong hiring and onboarding practices to ensure your employee files are as complete and correct as possible,” Gabriel said. “It is also a best practice to conduct periodic audits of I-9 records to identify and correct any discrepancies before ICE shows up.”

ICE or Homeland Security Investigations have the latitude to decide whether to audit Form I-9s.

Businesses will be issued a notice of inspection giving them three days to provide records, according to Legal Aid at Work, a workplace rights advocacy group. Employers must also post a notice for employees within 72 hours of receiving it — and it should be in the language or languages usually used to communicate with staff.

The posted notice for employers must include:

If immigration officials identify an employee as potentially lacking proper work authorization, or having deficiencies in their documentation, businesses will be notified and must provide the employee a copy of the findings within 72 hours.

Employers who operate in a union environment also must provide a copy of these notices to the employee’s representatives within that same time frame, according to the California Employers Assn.

According to the National Employment Law Project and the National Immigration Law Center, “If ICE decides you did not follow the Form I-9 rules” businesses may be ordered to stop hiring people who do not have valid work permits, and could face civil and criminal fines or other penalties.

A raid is when ICE agents arrive at a work site without warning the employer. They can be accompanied by other agencies or appear in large numbers, according to the California Employers Assn.

ICE agents can go to a business to try to find a particular person, or people, according to the National Immigration Law Center.

The California Employers Assn. recommends creating a four-step response plan that should address the following:

Who should be alerted: Alerting management and employee/union representatives within an organization can help reduce workplace disruption and keep employees calm, Gabriel said.

“Rumors and misinformation tend to create panic amongst a workforce and some employees may even try to flee or confront agents,” she said. “Running could give the agents reason to detain or arrest someone, so having an employee representative or member of management to maintain order and keep employees calm is advisable.”

Legal counsel should immediately be notified when ICE shows up because they can help “protect your organization and your employees from agents overstepping their boundaries or taking liberties as far as what they are authorized to do at your workplace,” she added.

Authorized speakers: Examples of people who can be designated to speak with agents include the business owner or a member of the management team, such as a general manager or human resources representative.

“Ideally it would be someone familiar with your response plan, if you have one, and authorized to speak on behalf of the company,” Gabriel said.

The identified person or people should be able to communicate confidently, clearly and remain composed “while protecting the privacy of your organization and its employees,” she said.

Gathering ICE agent information: You have the right to ask immigration officials which agency they represent as well as for their names, badge numbers and business cards.

“There have been reports of citizens impersonating ICE agents to target, detain and harass others,” Gabriel said.

Designated waiting area: Find a conference room or office where agents can wait. This can limit workplace disruptions.

Businesses should enact their response plan immediately when immigration officials arrive.

Before ICE agents can enter private areas of your business (public areas are parking lots or lobbies) they must present a valid warrant to conduct their search.

A valid warrant must be:

Businesses should ensure that employees know their rights and that they should refrain from engaging with ICE officials, according to the National Employment Law Project. If ICE agents have questions or requests, workers should not respond and instead direct the officials to speak with their employer.