() Immigration attorney Saman Nasseri says permanent residents and individuals with valid visas returning to the United States are facing increased scrutiny and detention at the border under the Trump administration’s enhanced vetting procedures.

“I’m seeing more residents that are getting detained and questioned coming back into the United States,” Nasseri told on Monday, though he noted he personally hasn’t heard from U.S. citizens experiencing similar issues.

The stricter procedures particularly affect residents who travel frequently. Border agents are closely monitoring how much time permanent residents spend outside the country to ensure they’re maintaining their U.S. ties and not abandoning their residency status, Nasseri said.

Nasseri confirmed that border officials can search travelers’ phones, emails and other communications a practice that has existed for years but has intensified recently.

“You have to assume they always know more than you think they know,” he said. “They’re looking at everything now.”

According to Nasseri, officials are flagging individuals based on travel history, criminal records, family connections and destinations visited.

U.S. citizens may face questions if they’re traveling with visa holders or living with individuals who are in the U.S. illegally.

“Right now, there is just a more extreme vetting process,” Nasseri said. “If a U.S. citizen is married to someone who’s undocumented, they’re living in that household, that can cause concern for DHS and border patrol now.”

The attorney advised permanent residents planning to be abroad for more than six months to file for a reentry permit. He also recommended that those with criminal records consult with an attorney before traveling internationally.

The increased border scrutiny comes amid high-profile detentions of international students from American universities, including cases involving students from Tufts University, the University of Alabama and Columbia University.

Several countries, including the United Kingdom, Finland, Germany, Denmark, and Canada, have issued travel warnings to their citizens regarding U.S. travel.

When asked about what changes might come next, Nasseri predicted continued pressure on U.S. Citizenship and Immigration Services, the Department of Homeland Security and Border Patrol to develop solutions for the immigration system.