A top Kazakhstan police official says attempts to hold demonstrations against a land-reform measure have been blocked and the prosecutor's office says activists were arrested for trying to organize them.

Activists had called for demonstrations on Saturday against a government move to liberalize sale and rental of farmland to foreigners. Opponents fear Chinese farmers could acquire large swaths of land.

The prosecutor's office said about 40 organizers were arrested Friday and Interior Ministry official Igor Lepekha said Saturday that there were detentions at an attempted rally in the capital Astana. He said no demonstrations were held elsewhere, but did not specify if there were arrests.

Lepekha said organizers aimed to cause provocations and that caches of bottles and gasoline were found near two squares in Almaty, Kazakhstan's principal city.