WARSAW, Poland -- A top Polish veterinary inspector says investigations in his country have still not uncovered any evidence backing Irish claims that Poland was the source of horsemeat that ended up in Irish and British burgers.

Jaroslaw Naze, deputy head of Poland's General Veterinary Inspectorate, insisted Thursday that Ireland hand over more documentary evidence, including of labels on the suspected meet supplies, so that Polish officials can complete their own investigation.

Tensions have emerged in recent days between the two countries, both major meat producers whose industries could be damaged by the horseburger scandal.

Irish government officials and an Irish meat company have blamed the contamination of beef patties with horsemeat on meat imported from Poland.