Insurgents stormed a jail about dawn Tuesday in the Sunni Muslim heartland north of Baghdad, killing at least 19 policemen and a courthouse guard. Authorities said all 33 prisoners in the lockup were freed and 10 attackers were killed in the battle. In the capital, a powerful group of US senators met with interim Prime Minister Ibrahim al-Jaafari to discuss prospects for formation of a national unity government, a step viewed as all-important in working toward peace and a withdrawal of US troops from Iraq. Al-Jaafari said he believed Iraq's most difficult political hurdles had been crossed and predicted a new government would be ready in the coming weeks. "I hope that the formation of the new government does not last beyond April," al-Jaafari said.