The Department of State advises Americans to defer nonessential travel to Yugoslavia because of political tensions, ethnic demonstrations and disruption of travel.

Incidents in many areas of the country have included road blockades and injuries to bystanders, says a travel advisory issued by the department last month.Arbitary detentions, arrests and searches have involved Americans in some cases, it adds.

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The American Embassy in Paris warns that hotel accommodations in the city will be extremely difficult to obtain from May 30 to June 24 because of various events, including the Paris Air Show.

Visitors should make sure before arrival that they have confirmed reservations.

Deposits are required to hold reserved rooms during this period, the embassy reports, adding that cancellations must be made at least a week in advance.