More than 18,000 passengers converged on Cairo International Airport on Tuesday, frantic for a way out. Their numbers were eclipsed only by the 250,000 demonstrators massed in the capital’s downtown — the epicenter of a protest movement to oust Egypt’s ruler of 30 years, Hosni Mubarak.

The scene downtown was more organized than at the airport, where the strains of a week of unrest were showing on tourists and foreigners who for years had called Egypt home. Adding to the sense of urgency was an order from the U.S. State Department for all non-emergency personnel and their families to leave. Washington had, until Tuesday, just suggested it would be a good idea to go.

That was easier said than done.

“People holding tickets had difficulties getting on the plane, because the airport in Cairo is pure chaos,” Canadian tourist Tristin Hutton, 44, said after his plane landed at Germany’s Frankfurt airport. “The terminals are full of panicking people.”

EgyptAir, the national carrier, canceled about 100 of its nearly 150 scheduled international flights and halted its service after 5 p.m. until Wednesday morning. The carrier has been canceling about 75 percent of its flights because crew are either unable to make it because of curfews, or are too worried about leaving their families.

Officials said about 3,000 to 3,500 passengers were at the airport after the curfew went into effect for the night. In previous nights, that has meant the passengers were essentially stranded until the morning.

The family of the former tourism minister, Zohair Garanah, left Cairo on a Greece-bound private jet, marking the latest exit from the country by a member of Egypt’s reviled business and political elite. Protesters have complained that Mubarak’s regime favored the rich at their expense, and several wealthy businessmen are members of the parliament.

As the crowds at the airport grew, so did tensions.

A group of EgyptAir employees scuffled with passengers who rushed the ticket counter, desperate to secure a reservation, airport officials said, speaking on condition of anonymity because they were not authorized to brief the media.

Others tapped their government for help, and the planes came in droves. Airlines from around the world arranged about 85 flights to ferry people to their respective nations. The destinations included the more placid Libya, Kuwait and Saudi Arabia. The U.S. sent in more than a dozen charter flights on Monday and Tuesday to fly those citizens who wished to leave. More flights to the designated safe haven destinations of Cyprus, Turkey and Greece were expected Wednesday.

Even Baghdad’s roadside and suicide bombings appeared to be a more comforting prospect than remaining in a city where looters torched stores and youth turned out in the thousands, armed with clubs, shovels, machetes and the occasional gun to defend their neighborhoods. Iraq flew in three planes to evacuate its nationals, including the prime minister’s plane.

The violence in the Egyptian capital was etched in New York-resident Pamela Huyser’s memory. She had traveled to Egypt for a conference and had an birds-eye view of the unrest from her ninth-floor hotel balcony.

“You cannot even believe what we saw,” she said after arriving in Larnaca, Cyprus. “We saw people looting, we saw gunfire, people shooting other people. A lot of people working in our hotel, they came out with sticks and knives and bats and they protected us from getting looted.”

The parting image for others came in the form of a firsthand experience of the kind of corruption that some protesters said was the catalyst for their rage.

While complaining about the disappearance of ground staff at the airport, Hutton, the Canadian tourist, recalled that the passengers banded together to “collect $2,000 for a policeman at the door.”

“He would not let us pass without paying,” he said.

At a the terminal where the government-chartered flights departed, officials said more than 8,000 people were trying to leave. More than 35 flights flew out from that terminal.

Governments continued to warn against travel to Egypt, and many advised their nationals to avoid travel to the country — especially Cairo and Alexandria. The Red Sea resorts favored by the Europeans have so far been spared the unrest, but while thousands opted to stay put, others wanted out.

Most of the 3,500 Finns at resorts in Egypt have returned home on flights organized by their travel agencies. A 200-seat aircraft was to be sent to Cairo by the Finnish Foreign Ministry on Wednesday to evacuate those living in Egypt.

Britain said it had not ordered its staff to leave, but confirmed most diplomats’ families had left. Germany, meanwhile, expanded its travel warning to include Red Sea resorts, but did not order evacuations. Some 1.2 million Germans visit Egypt each year.

The panic and unrest appeared to be the most enduring memory for many who had come to Egypt anticipating exploring its monuments and sunning on the beaches.

Madeline Murphy Rabb, a Chicago-based curator, said that a Nile cruise to celebrate her 66th birthday was interrupted by the protests, with passengers confined to the ship at Luxor for two days.

“The manager of the tour ship restricted us from leaving the boat because he feared for our safety,” Rabb said in a telephone interview from London on Tuesday.

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Staff in Associated Press bureaus around the world contributed to this report.