Police in Kenya have arrested an assistant minister and an MP for hate speech in the campaign for a new constitution, after violence on Sunday.
Assistant Roads Minister Wilfred Machage and Fred Kapondi were among six MPs accused of hate speech on Monday.
All six are being questioned and deny the charges.
Six people died on Sunday after a grenade attack at a prayer meeting in the capital, Nairobi, organised by the "No" campaign.
The six MPs, including Higher Education Minister William Ruto, are appearing at the National Cohesion and Integration Commission (NCIC).
The commission has also written to President Mwai Kibaki and Prime Minister Raila Odinga, asking for the suspension of all campaigning over the constitution, ahead of a referendum planned in August, reports the Daily Nation newspaper.
Some fear a return of the violence seen after the December 2007 elections, which left some 1,300 people dead and 300,000 homeless.
Church leaders accused the government, which is mostly campaigning for a "Yes" vote, of being behind Sunday's attack, which led to a stampede at the rally.
Many Kenyans doubt the Church leaders' claim that the government could be behind the blasts, especially as it seems most people are already backing the "Yes" campaign, says the BBC's Will Ross in Nairobi.
Prime Minister Odinga on Monday said the attack was being investigated and called for an end to speculation about who is responsible until the inquiry is concluded.
Much of the post-election violence in 2008 was over land disputes between rival ethnic groups and the draft constitution would set up a land commission to manage public and community land, which is opposed by some.
The violence ended when election rivals Mr Kibaki and Mr Odinga agreed to share power - and write a new constitution.
The coalition remains shaky but supporters of both men generally support the draft constitution.
The document provides for greater checks on presidential powers and more regional devolution.
It also recognises the UN human rights charter and creates a second parliamentary chamber - the senate.
Sunday's rally was organised by Christian groups opposed to a draft constitution because it retains recognition of existing Islamic courts and includes a clause on abortion.
The Islamic Kadhi courts - set up under British colonial rule - mainly deal with matters of marriage and inheritance for Kenya's Muslim minority.