BAGHDAD — As Iraq prepares to showcase itself to the world next week with a highly anticipated gathering of Arab leaders, a string of suicide attacks and car bombings on Tuesday morning offered a bloody reminder that insurgent violence still wreaks havoc with the country’s tenuous stability.

The attacks killed at least 43 people in a half-dozen cities across the country, security officials said, from a Shiite pilgrimage site in the south to a disputed, ethnically diverse center of Iraq’s oil wealth in the north. More than 100 people were wounded, and while there were no immediate claims of responsibility, the scale and synchronicity of the bombings were nearly identical to previous attacks by the Sunni insurgent group Al Qaeda in Iraq.

In the capital, two explosions not far from the International Zone — a hub of government and diplomacy — and a frontal attack against a Christian church undercut the government’s rigid efforts to inoculate Baghdad from threats as it prepared for thousands of Arab leaders, diplomats, journalists and others to arrive for the Arab League summit meeting. It is the first such meeting in Iraq since 1990, and Baghdad’s first major diplomatic event since the last American soldiers departed in December.

Iraq is spending about $500 million on the meeting, for extensive security and for everything from hotel renovations and overtime to catering, stationery and new sod and palm trees on the road from the airport. Foreign Minister Hoshyar Zebari called the price tag “an investment for the country.”