BAGHDAD (Reuters) - At least 16 near-simultaneous explosions struck cities and towns across Iraq on Tuesday, killing at least 43 people and wounding more than 200, despite a massive security clampdown ahead of next week's Arab League summit. It was Iraq's deadliest day in nearly a month, and the breadth of coordinated bombs in more than a dozen cities showed an apparent determination by insurgents to prove that the government cannot keep the country safe ahead of the summit. Iraq is due to host the meeting for the first time in 20 years and the government is determined to show it can maintain security following the withdrawal of US troops in December. Tuesday's deadliest incident occurred in the southern Shi'ite Muslim holy city of Kerbala, where twin explosions killed 13 people and wounded 48 during the morning rush hour, according to Jamal Mahdi, a Kerbala health department spokesman. "The second explosion caused the biggest destruction. I saw body parts, fingers, hands thrown on the road," 23-year-old shop owner Murtadha Ali Kadhim told Reuters. "The security forces are stupid because they always gather at the site of an explosion and then a second explosion occurs. They become a target." Within about two hours blasts also struck in the capital, in Kirkuk, Baiji, Samarra, Tuz Khurmato, Daquq and Dhuluiya to the north, in Ramadi in the west, and Hilla, Latifiya and Mahmudiya in the south. Police defused bombs in Baquba and Falluja. Most of the blasts targeted police <b>...</b>