WARSAW, Dec 23 (AFP) - The Polish government will send a special envoy to Grozny to investigate the kidnapping of five Poles near the Chechen capital, Polish Foreign Minister Bronislaw Geremek said Tuesday.

The five Poles, joint organisers of a humanitarian aid convoy to the village of Samashka, near Grozny, were kidnapped last Wednesday as they returned from a meeting with authorities in the town, the Polish foreign ministry said earlier.

"They placed too much faith in their experience and did not respect the rule of not travelling at night," the official in charge of the Organisation for Security and Cooperation (OSCE) bureau in Grozny Leon Wascinski was quoted as saying by Polish radio.

Ministry spokesman Pawel Dobrowolski said the Poles' truck had been found last Thursday with its front tyres riddled with bullet holes on a road between Samashka and Grozny.

The rest of the vehicle was untouched and no traces of blood were found on or near it, indicating that the five occupants might be unhurt, Dobrowolski said.

The five men, who were working for an aid organisation, were last seen in Grozny on Wednesday.

"We still don't know who kidnapped them or why," the spokesman told AFP. "We can presume that, as in similar incidents, a ransom will be demanded."

Wife of one of the hostages Anna Niedzwiedzka-Galinska said it was a matter of "Russian provocation," adding that the motive was either to obtain a ransom or, more probably, it was part of the "struggle between Chechen clans."

So far the kidnappers have issued no demand.

The Russian foreign ministry confirmed the kidnapping and renewed its appeal for foreigners to stay away from the breakaway republic of Chechnya.

A ministry statement quoted by the Interfax news agency said the abductions prove "the continuation of the extremely unfavourable criminal situation in Chechnya."

Since the end of the Chechen war in August 1996, around 50 people have been kidnapped, mainly British, Swiss and Hungarians.

The Polish press reported that two of the five men had met with the former Chechen president Zeli Khan Yandarbiyev.

Their trip to take food supplies, medicines and furniture to Samashka, one of the villages hardest hit in the war, was organised by the aid organisation Caritas run by the archbishop of the northern Polish city of Gdansk.

Polish newspapers identified the men as Marek Kurzyniec, Dominik Piaskowski, Marcin Thiele, Krzysztof Galinski and Pawel Chojnacki.