KIEV, Ukraine — Ukraine’s Parliament on Tuesday ordered law enforcement agencies to immediately disarm unofficial paramilitary groups, signaling growing resolve in the interim government to confront nationalists and other vigilantes who played a big role in the overthrow of Viktor F. Yanukovych, the country’s pro-Kremlin former president who was deposed more than a month ago.

The bill, introduced and passed unanimously, ordered both the Interior Ministry and the Security Service of Ukraine, the country’s successor to the K.G.B., to disarm the groups because of the “aggravation of the crime situation and systematic provocations on the part of foreigners in southeastern Ukraine and in Kiev.”

The attempt to further consolidate control domestically came as Russia delivered yet another blow to the fledgling Ukraine government, which the Kremlin regards as illegal. Gazprom, the Russian state gas giant, announced a 40 percent increase in the price of natural gas sold to Ukraine, which is heavily dependent on Russia for its gas supply.

The passage of the anti-paramilitary bill comes as tensions in Kiev, the Ukrainian capital, have grown between nationalist groups who continue to patrol the main squares of the city and Arsen Avakov, the country’s new interior minister.