Although the sentence is milder than a jail term, it is considered unusually heavy for the offense of which they were convicted. Usually, activists get two-week prison terms or fines for organizing banned rallies.
Some analysts say the sentence reflects intensifying repression in Belarus.
Alyaksandr Sosnov, deputy director of the Minsk-based Socio-Economic and Political Studies Institute, says the authorities seek to destroy all opposition ahead of presidential elections set for the autumn of 2006.
"The authorities understand perfectly well that it is impossible for them to win in a fair way," Sosnov says. "They need to falsify these elections. But to do that they need to make silent those who speak openly."
Sosnov says that Ukraine's recent Orange Revolution frightened Lukashenka. The president has vowed publicly that he will not allow similar events to take place in his country. He has repeatedly demonstrated his readiness to use force when threatened.
Sosnov says that the confinement of Statkevich and Sevyarynets is unlikely to change the society. He says that Belarusian opposition politicians have learned to live with harassment as a part of life. He says that not only politicians but also any independent political organization is subject to scrutiny and, often, unmerited punishment.
"Repressions are under way against nongovernmental organizations," Sosnov says. "They are being closed on a constant basis. Similar repressions are under way against independent mass media."
Sosnov says the authorities are in the process of closing down the Institute for Socio-Economic and Political Studies itself -- for the trivial reason of not using its official name in full.
Last week, Belarusian authorities confiscated nearly 2,000 copies of the independent newspaper "Den," published in Russia. The move came just days after the Belarusian Information Ministry asked its Russian printers to halt publication.
Belarus authorities announced on 1 June that nongovernmental organizations and independent media no longer will be permitted to include "Belarusian" or "National" in their titles. Belarusian media advocates say the move appears aimed at shutting down independent newspapers and at making new registration more difficult.
Sosnov says that polls being conducted by the institute on a regular basis show that a slump in Lukashenka's popularity is under way: Sosnov says some 47 percent of people who participated say they support the president.
"It is comparatively a lot but it is less than 50 percent," Sosnov says. "It is less than it was before. So, gradually more and more people refuse to support the Belarusian authorities. In other words, the support of the society is going down and it is evident."
Kirill Koktysh, an analyst with the Moscow Institute of International Relations, says the sentence might may actually have a positive impact on the opposition, by making the prosecutions appear to be ridiculous overkill.
"There is unlikely to be anything more that can weaken the Belarusian opposition. On the contrary it might lead to its strengthening," Koktysh said. "The reason is simple -- the number of jailed opposition members is over all acceptable norms and we can without any doubts say that those people who were not jailed were never in opposition."
Sosnov says the opposition to Lukashenka is largely silent. He says that more repression of even minimally vocal opponents appears to be imminent.