Iraq's president named former communications minister Mohammad Allawi as the country's new prime minister on Saturday after an 11th-hour consensus among political blocs, but the streets seemed divided on his nomination.

Baghdad and the mainly Shia south have been gripped by four months of anti-government rallies demanding snap elections, a politically independent prime minister and accountability for corruption and protest-related violence.

Faced with pressure from the street and the Shia religious leadership, Prime Minister Adel Abdel Mahdi resigned in December and political life came to a standstill.

In a bid to end the paralysis, President Barham Saleh gave political blocs until Saturday to name a replacement to Abdel Mahdi or else he would appoint his own candidate.

On Saturday evening, Allawi posted a video to Twitter saying Saleh had nominated him as the new premier. "After the president appointed me to form a new government a short while ago, I wanted to talk to you first," he said, addressing the camera in colloquial Iraqi dialect. "I will ask you to keep up the protests, because if you are not with me, I won't be able to do anything," Allawi said.

There was no formal announcement from Saleh or other government bodies, and the main protest camp in Tahrir Square seemed split on his nomination. "Allawi is rejected, Allawi is rejected!" some protesters chanted, but others appeared to rally in support of him.

According to the constitution, Allawi now has one month to form his cabinet, which would need a vote of confidence from parliament. In Iraq, the cabinet is typically formed by consensus among political rivals after intense horsetrading over influential posts. "If the (political) blocs try to impose their candidates on me, I'll come out and talk to you and leave this nomination," Allawi said. Allawi served as communications minister twice under former PM Nuri al-Maliki but resigned both times, alleging corruption. Shortly before Allawi's announcement, protesters in Tahrir expressed reservations about anyone with previous government experience assuming the premiership and frustration with the slow pace of reforms.

Protests in Tahrir swelled on Saturday as supporters of Shia cleric Moqtada Sadr returned to the streets. Sadr controls parliament's largest bloc and many ministerial posts, but he backed the protests when they erupted in October and his supporters were widely recognised as the best organised demonstrators.