Al Qaeda's affiliate in Iraq has claimed responsibility for scores of attacks across the country targeting mostly Shi'ite Muslim targets this week which killed and wounded hundreds of people.The Islamic State of Iraq (ISI) said in a statement posted on radical Islamist websites on Tuesday that it was behind the recent attacks, which it called its "Destroying the Walls" campaign and said was the start of a "new stage of jihad".At least 116 people were killed and about 300 wounded in bomb and gun attacks on Monday, by far the bloodiest day of violence since U.S. troops withdrew in December. A day earlier 20 were killed in bombings as part of a co-ordinated surge of violence."The Ministry of War has mobilized its sons and mujahideen brigades and their military groups in a new blessed foray in the holy month of Ramadan," the ISI statement said."Simultaneous and co-ordinated jihadist operations have swept across the country in a spate which stunned the enemy, made him lose his sense and showed the failure of intelligence and security plans which filled the world with noise and bluster." The bloodshed coincided with an intensifying of the conflict in neighboring Syria. Iraqi officials have warned that al Qaeda militants are passing in and out of Syria through the 680 km (420 mile) border between the two countries, and Baghdad has sent troops and tanks to the frontier to strengthen security.