NARITA, Japan -- Japanese officials delayed Paris Hilton at Narita International Airport while they decide whether she will be admitted to the country after pleading guilty to a misdemeanor drug charge in Las Vegas.

The 29-year-old celebrity was stopped by immigration authorities upon her arrival in Japan on Tuesday, one day after her plea, according to an e-mailed statement by Hilton's representative, Dawn Miller.

Hilton was scheduled to appear at a news conference in Tokyo on Wednesday to promote her fashion and fragrance lines, but that appearance was canceled.

Immigration authorities questioned Hilton "for undisclosed reaons," and she was not allowed to enter the country, Hidekazu Akai, an immigration official at Narita, said early Wednesday.

The officials adjourned questioning and asked Hilton to stay at a hotel in the airport so they could continue immigration procedures Wednesday, Kyodo News agency reported. The front desk at her hotel said calls to her room could not be connected.

Under Japanese law, immigration authorities are empowered to deny entry to those who have been convicted of drug-related offenses.

Officials at the U.S. Embassy in Tokyo declined to comment.

Tokyo was the first stop on Hilton's planned Asia tour, during which she planned to visit Kuala Lumpur, Malaysia, and open a new retail store in Jakarta, Indonesia. Both countries have strict anti-drug laws and immigration procedures, and it was unclear whether Hilton would continue her travels.

Miller's statement said Hilton was disappointed with the scrutiny by Japanese authorities.

"Paris was contractually bound to her business trip and didn't want to let down her brands and many Asian fans," the statement said. "She intended on fulfilling her contract and is trying hard to do the responsible thing, but this is beyond her control. She is very disappointed by tonight's events."

Hilton appeared with Nicole Richie on the series "The Simple Life" and has since starred in another reality series and minor films.

The Asia trip had been planned before Hilton's arrest last month in Las Vegas, when an officer found a small amount of cocaine in her purse. She pleaded guilty Monday to drug possession and obstructing an officer and was placed on informal probation for one year.

The terms of her sentence did not restrict travel overseas.

"We have no legal basis to restrict her from traveling throughout the United States or throughout the world," Clark County District Attorney David Roger said.

Hilton's sentence also requires her to complete a drug program, pay a $2,000 fine and serve 200 hours of community service. Her attorney said Monday that she planned to complete the service by volunteering with animal advocacy groups and children's hospitals.

Hilton served 23 days in a Los Angeles-area jail in 2007 after she was found to have violated her probation on an alcohol-related reckless driving case.

She also was detained in South Africa in July during the World Cup on suspicion of marijuana possession, but the allegation was dropped when another woman in her group pleaded guilty to carrying the drug.