Multiple car bombings have killed at least 35 people in Baghdad -- as the United States calls on Syria to do more to prevent the entry of foreign fighters into Iraq. Four car bombs rocked a Shi'ite neighborhood in Baghdad early Thursday, killing at least 17 people. Hours earlier, a triple car bombing killed at least 18 others in another Baghdad neighborhood. Dozens were wounded in the attacks. Meanwhile, US Secretary of State Condoleezza Rice called on Syria to follow through on a pledge to secure its border with Iraq. US officials say foreign fighters continue to pour into Iraq from Syria. Separately, an Internet message attributed to insurgent leader Abu Musab al-Zarqawi said Abdullah Mohammed Rashid al-Roshoud -- another leading suspected al-Qaida militant -- was killed in a US air strike in northwestern Iraq.