Saudi Arabia and Qatar are supporting militant groups in Iraq and have effectively declared war on the country, Prime Minister Nuri al-Maliki said as nationwide violence left 15 dead Saturday.

The rare direct attack on the Sunni Gulf powers, with Maliki also accusing Riyadh of supporting global terrorism, comes with Iraq embroiled in its worst prolonged period of bloodshed since 2008, with more than 1,800 people killed already this year, ahead of parliamentary elections due next month.

The bloodletting in Iraq, which shares a long border with Saudi Arabia, has been driven principally by widespread discontent among the country's Sunni Arab minority and by the civil war in neighbouring Syria.

Maliki, a Shiite, has in the past blamed unnamed regional countries and neighbours for destabilising Iraq.

But in an interview with France 24 broadcast on Saturday, the Iraqi premier said allegations he was marginalising Sunnis were being pushed by "sectarians with ties to foreign agendas, with Saudi and Qatari incitement".

Referring to the two countries, he said: "They are attacking Iraq, through Syria and in a direct way, and they announced war on Iraq, as they announced it on Syria, and unfortunately it is on a sectarian and political basis."

"These two countries are primarily responsible for the sectarian and terrorist and security crisis of Iraq."

Saudi Arabia and Qatar have emerged as regional rivals because, while both have provided support to fighters opposed to embattled Syrian President Bashar al-Assad, the two countries have also sparred in recent weeks over Doha's support for the Muslim Brotherhood of deposed Egyptian president Mohamed Morsi.

Saudi Arabia, along with Bahrain and the United Arab Emirates, withdrew its ambassador to Qatar this month.

Baghdad has long complained that support for militant groups fighting in Syria's civil war finds its way through to Iraq with weapons in particular ending up in the hands of jihadists.

Maliki said in the interview that Riyadh and Doha were providing political, financial and media support to militant groups and accused them of "buying weapons for the benefit of these terrorist organisations".

- 'Dangerous Saudi stance' -

In the interview, Maliki also accused Saudi Arabia of supporting global terrorism, both inside the Arab world and in other countries.

He slammed "the dangerous Saudi stance" of supporting "terrorism in the world -- it supports it in Syria and Iraq and Lebanon and Egypt and Libya and even in countries outside" the Arab world.

Maliki in January blamed "diabolical" and "treacherous" Arab countries but has consistently refused to point directly at particular states.

But, as violence has worsened markedly in Iraq -- the death toll from attacks and clashes last month was more than triple that of February 2013 -- and with elections due on April 30, Maliki has taken a hard line, pushing security operations against militants.

He has also called for greater coordination against militancy, with Baghdad due to host an international counter-terrorism conference on March 12.

On Saturday, violence nationwide killed at least 15 people, including a parliamentary election candidate -- the second murdered this year -- and four children, security and medical sources said.

Election candidates have been targeted in the past, with nearly 20 killed ahead of April 2013 provincial council elections.

Attacks in Baghdad and north of the capital, meanwhile, left 14 others dead.

Violence has killed at least 110 people so far this month, and more than 1,800 since the beginning of the year, according to AFP figures based on security and medical sources.

Diplomats and analysts have urged Iraq's Shiite-led authorities to pursue reconciliation with the Sunni minority in addition to security operations, but political leaders have been loath to compromise ahead of elections and have offered little in the way of concessions.

And while officials have trumpeted moves against militants for months, violence has remained at its worst since Iraq emerged from a brutal Sunni-Shiite sectarian war in 2008, and anti-government fighters have held control of Fallujah, a major city on Baghdad's doorstep, for more than two months.