Four rockets struck the town of al Qaim, which is also home to a Syrian refugee center, CNN reported.
The Iraqi foreign ministry cautioned Syria to avoid future strikes.
"Although Iraq has taken a neutral position in the Syrian conflict ... our brave forces are ready to respond in case (of) repetition of such attack," the ministry said in a statement.
A pipeline that provided drinking water to millions of residents in Aleppo ruptured Saturday, adding to the country's humanitarian crisis, The New York Times reported. More than 1.2 million people, half of them children, who have been driven from their homes are receiving assistance from a U.N. refugee agency.
Rebel forces blamed the pipeline break on shelling from government helicopters. The water flooded two neighborhoods in the north of the city, said opposition groups, the Syrian Observatory for Human Rights (SNHR) and the Local Coordinating Committees.
Majed Abdulnoor, an activist and informal spokesman for the rebels, said the bombs that burst the pipeline were in response to a rebel force that tired to cut off food and water to a contingent of regime soldiers in the city. The shells were fired in an attempt to free the building, he said.
SNHR said it had documented the deaths of 129 people Saturday, including 15 children and five women.
Nearly half of the dead were victims of random shelling, SNHR reported.
SNHR said 33 people were killed in Damascus and its surrounding area, 31 in Aleppo and 21 in Homs.