"Our humanitarian work has been hampered since the main bridges and highway overpasses in Baghdad and other provinces started to come under attack," said Abdul-Hamid Salem, director of the ICRS's Baghdad office.
"Sometimes it takes us a very long time to transport aid between the two main parts of Baghdad as the authorities do not allow trucks capable of carrying more than two metric tonnes to cross before 3pm to prevent further attacks," Salem said.
"So we have to wait until after 3pm to cross and that of course undermines our efforts to help those who need our help," he added.
The IRCS, he said, was investigating the possibility of having at least six two-tonne trucks travel freely around Baghdad.
Baghdad bridges under attack
Three of Baghdad's 13 bridges over the River Tigris have been targeted by large explosions since March. Iraqi and US commanders say they are studying the attacks, which they term "desperate acts by insurgents who are under pressure from the five-month old Baghdad security operation".
Some analysts see the attacks on the bridges as an attempt to make it difficult for Iraqi and US troops to bring supplies from one side of the river to the other. Others believe the goal is to divide the city's predominantly Shia east bank, known as Risafa, from the mostly Sunni west bank, or Karkh.
"Obviously we see a shift in their tactics and we are taking appropriate security measures to make sure all supply lines continue to stay open," said Col Ahmed Abdullah Hassan of the Iraqi Interior Ministry.
"The extremists, the terrorists, are looking to find ways to divide and create terror and make life difficult for the people of Iraq," Abdullah added.
Recent attacks on bridges
The first attack on a bridge took place on 21 March, when security forces discovered a booby-trapped truck parked on the Mohammed al-Qassim bridge in northern Baghdad. The explosives were covered with boxes of fruits and vegetables.
Security forces did not have enough time to de-activate the bombs so they evacuated the area and blew up the truck, causing some damage to the bridge. Although the area was evacuated, one civilian was killed and seven were wounded in the powerful blast.
The most serious attack occurred on 12 April when a suicide truck bomb destroyed a steel girder on Sarafiyah Bridge, causing cars to plunge into the water. Eleven were killed and 39 wounded. Seven cars were pulled from the river.
Two days later, a suicide car bomb killed 10 people on Jadriyah Bridge, which, however, suffered little damage.
In June, suspected Sunni insurgents bombed and badly damaged a span over the main north-south highway leading from Baghdad.
A few days prior to that, another bridge south of Baghdad was destroyed by what was believed to be a suicide truck bomber. Three US soldiers guarding that bridge were killed in the blast.
In another place, a parked truck bomb destroyed a bridge carrying traffic over the River Diyala in Baqouba, 35 miles northeast of Baghdad. There were no casualties, but vehicles were being forced to make a detour.