No ransom demands have been made for the four hostages, Chechnya's acting Security Minister Aslambek Arsayev said.
Mr Arsayev said that investigators believe the four may be held by the same gang that kidnapped another high-profile hostage, the Russian presidential envoy Valentin Vlasov, Russia's Itar-Tass news agency reported. Mr Vlasov was kidnapped on 1 May and remains missing.
The hostages - Britons Peter Kennedy, Darren Hickey and Rudolf Petschi, and Stanley Shaw from New Zealand - were kidnapped on 3 October. They were working for Granger Telecom, a British telephone company.
Chechnya's security forces launched a 10-day crackdown last week, seeking to capture rebel armed groups and possibly find leads to the hostages. A search is being conducted in Chechnya's mountainous regions, where hostages are usually held, Mr Arsayev said.
Several suspects in other cases have been detained during the operation, and dozens of firearms and more than 18kg of marijuana have been seized, he said. However, no leads to the hostages have been found.
Mr Arsayev has said that investigators believe the four telecoms hostages are being moved from place to place.
Hostage-takings, usually for ransom, have become common in Chechnya since the end of its two-year war for independence from Russia in 1996.
Since the beginning of 1998, 176 people have been kidnapped in the North Caucasus region of Russia and 90 of them released. Of the 176, 46 were foreign nationals, and seven foreigners were still being held in addition to the four captured 10 days ago: two Turks, a Frenchman, a Yugoslav, a Slovak, a Saudi, and a Slovene.Reuse content