Nongovernmental organizations are scrambling to file their accounting paperwork to authorities by a deadline Sunday, exactly one year after a controversial law on NGOs came into effect.

All NGOs must file their annual reports to the Federal Registration Service by Sunday or risk facing closure, and NGO representatives said Wednesday that they are suffocating under the additional paperwork required under the revamped law.

"There too many details we have to provide, and it's confusing trying to distinguish between 'main' events, which have to be included in the reports, and other events, which don't have to be," said Tatyana Kasatkina, executive director of the human rights group Memorial.

Boris Altshuler, head of the Right of the Child advocacy group, said his organization was required to file so much paperwork that it was virtually impossible to do anything else.

Kirill Yezhov, spokesman for Charities Aid Foundation Russia, said larger NGOs such as his face fewer difficulties in making the deadline because they have lawyers and accountants working exclusively on filing the required paperwork. "It's much more difficult for smaller NGOs who simply can't handle such large amounts of paperwork," Yezhov said.

Registration service official Zhanna Fedyushkina said the agency had sent recommendations to NGOs on submitting their paperwork, but that a vast majority had yet to file.

Those that miss the Sunday deadline will be issued a warning, which, if ignored, could lead to closures, Fedyushkina said.

The new requirements are especially problematic for human rights groups that receive most of their financial support from abroad. NGOs must, among other things, list all foreign donations received and specify exactly how those funds were used.

State Duma Legislation Committee chairman Pavel Krasheninnikov said Wednesday that there was nothing wrong with foreigners funding NGOs involved with humanitarian work, but that foreign funding of political activities must not be allowed.