Berne - Switzerland has advised its citizens not to visit Libya because of a row triggered by the temporary arrest of Moammer Gaddafi's son, officials said Wednesday.

The Swiss Foreign Ministry voiced concern at what it described as "alarming" retaliatory measures introduced by the Libyan leader in the wake of his son Hannibal's detention in Geneva a week ago.

Since last Thursday Gaddafi's government has detained Swiss citizens in Libya, demanded the closure of Swiss firms present in the country and recalled its diplomatic representatives to Switzerland, the ministry said.

Libya has also stopped processing visa requests from Swiss. On Wednesday, it ordered the airline, Swiss, to reduce its flights to Tripoli from three to one a week.

Hannibal Gaddafi and his pregnant wife, Aline, were arrested on July 15, following complaints they inflicted physical injuries on two of their domestic staff.

Gaddafi spent two nights in a cell and his wife was detained in hospital before they were released on bail of 500,000 Swiss francs (490,000 dollars).

The couple, who left the country after their release, denied harming the two maids from Tunisia and Morocco. (dpa)