Opposition politicians threw chairs and attacked the parliamentary speaker during a violent general strike in Nepal on Tuesday that was aimed at blocking the government from pushing through a draft of a new constitution.

The Constituent Assembly began meeting at 2 a.m. Tuesday, and the violence started when opposition members tried to stop Speaker Subash Nemwang from proposing the formation of a questionnaire committee, which precedes voting on the constitutional draft later in the week.

They threw chairs, kicked over desks and tossed microphones at the speaker. In the tussle, several security guards were injured but the Assembly members suffered only bruises.

The ruling coalition - which has support of two-thirds of the members in the 605-member assembly - plans to push through the draft on Thursday. Opposition parties say any new constitution should be adopted only through consensus among all political parties.

The alliance of 30 opposition parties called the general strike to protest, and shut down schools, transportation and shops. Supporters chanted anti-government slogans at rallies in the capital, Kathmandu, clashed with police set a dozen vehicles on fire when their owners defied the strike call.

Police detained about 50 protesters who were trying to enforce the strike.

Nepal has been attempting to draft a constitution since electing its first Constituent Assembly in 2008. The second assembly was elected in 2013 but disagreements among the political parties continue to hamper progress.