MOSCOW — Opponents of the interim government in Kyrgyzstan stormed administration buildings in three southern cities on Thursday, forcibly installed a new governor and seized an airport apparently in an attempt to take power in the south a month after the country’s president was ousted in an uprising.

After seizing the buildings, the protesters issued a statement demanding the return to power of the former president, Kurmanbek Bakiyev.

It was the worst turbulence in Kyrgyzstan since the bloody uprising that led to the overthrow of Mr. Bakiyev last month. He is in exile in Belarus, but he retains support in his homeland in the south of the country, where discontent has been rising.

Kyrgyzstan, a landlocked mountainous nation in the heart of Central Asia, hosts a military base important to the United States’ war efforts in Afghanistan. Russia, which considers Kyrgyzstan within its sphere of influence, has opposed the base.