Kuwait City: Kuwait ordered its interior ministry on Monday to review the citizenship of people who threaten national security and vowed an “iron fist” policy, in a crackdown on dissent following violent protests.

Riot police earlier this month clashed with demonstrators protesting over the arrest and detention of prominent opposition leader Musallam Al Barrak for allegedly insulting the judiciary.

Several people were hurt and about 50 others arrested, most of whom have already been bailed.

In a string of decisions against “acts of riots and violence”, the cabinet of the Gulf nation ordered the interior ministry to start screening citizenship of people “who undermine the country’s security and stability”.

It also warned of penalties for non-profit organisations which involve themselves in politics.

The cabinet, in a statement, asked “the interior ministry to take all necessary measures to ensure that terms and conditions for citizenship and national belonging contained in the nationality law are fully met, particularly with regard to practices undermining security and stability”.

It also called on the ministry to stop NGOs from instigating unrest.

The cabinet pledged “an iron fist policy and a decisive and firm confrontation with whatever could undermine the state, its institutions and constitution”.

Al Barrak was detained for six days for allegedly criticising the judiciary at a public rally last month.

At the rally, Barrak also alleged that former senior officials, including ruling family members, had stolen tens of billions of dollars from public funds and accused them of money-laundering.

The scandal was later linked to claims that the same officials were seen in video footage plotting a coup.

Those allegations were made in a lawsuit filed last month by Shaikh Ahmad Fahd Al Sabah, a senior ruling family member and former energy minister.

Shaikh Ahmad was himself questioned as a witness.

The new developments plunged the nation into a new political crisis following months of relative calm.

Since mid-2006, the Gulf nation was rocked by a series of political crises leading to parliament being dissolved six times.

Most opposition groups are not represented in parliament after boycotting a July 2013 election in protest at an amended Kuwaiti electoral law.