Swiss nationals are being advised by the government to avoid travelling to the Middle East due to the uncertain security situation there following the terrorist attacks in the United States.
The ministry's warning comes after the United States threatened to launch military strikes against Afghanistan unless the country's ruling Taliban hand over the suspected terrorist, Osama bin Laden.
It said people intending to travel to Pakistan, Iran and parts of north Africa should be aware that they may be at risk and should monitor the situation in those areas before their departure.
However, swissinfo has learned that there are no specific plans to evacuate the 200 Swiss nationals in Pakistan's capital, Islamabad. Ministry spokesman, Markus Börlin, said Swiss nationals in Pakistan were being closely monitored, but the final decision on whether to leave would be left up to them.
"Of course we will assist them and check to see what other countries are doing, but the final decision is up to them," he said. "We do not give orders to leave countries, but as a last resort we would recommend that they leave."
Pocket knives banned
In a further development Swiss airports have banned the sale of pocket knives following reports that one of the suspected hijackers in last week's terrorist attacks in the United States may have purchased knives in Switzerland.
Authorities said at least one hijacker spent time in Switzerland. The Attorney General's Office has opened a formal investigation into whether Switzerland was used as a base for terrorist activities.
Hans-Jürg Widmer, a spokesman for the Attorney General's Office, said investigators were working flat out to try to hunt down any links to Tuesday's attacks on Washington and New York.
"We are under enormous pressure because of the importance of the investigation," he said. "There are connections in Italy and Germany, and we need to establish what went on in Switzerland."
100 Swiss still missing
The Foreign Ministry said around 100 Swiss still remained unaccounted for in the US. The ministry admitted it was having difficulty tracking down the missing, many of whom are believed to be tourists. Two psychologists have now been sent to New York to help any Swiss nationals who need counselling.
The Swiss consulate in New York said on Tuesday that it was concerned about the whereabouts of ten Swiss nationals who have been missing since last Tuesday. The consul general, Jacques Reverdin, said the search could go on for several weeks.
Speaking on Swiss radio, the foreign minister, Joseph Deiss, said Switzerland was ready to work alongside the international community to combat terrorism. "There is no neutrality in the face of terrorism," he said.
However Deiss was less forthright on the issue of whether Switzerland would allow Nato to use Swiss airspace. He said the government would need to know the nature of operation and whether it had United Nations Security Council approval before granting permission.
Deiss insisted that military reprisals would be pointless unless directed against the terrorists themselves. He added that any military strikes launched by the US would have to be discussed with the international community beforehand.
swissinfo with agencies