Gunmen armed with rocket-propelled grenades have ambushed a police convoy in eastern Punjab province, killing at least 11 officers and wounding seven others, authorities said. No one immediately claimed responsibility for the attack on Thursday in the Rahim Yar Khan district. The officers were ambushed while on patrol in a deserted area in search of robbers who operate in the region. Punjabi police said the gunmen were probably robbers and not militants. The victims were taken to a nearby hospital. There has been a surge in violence and attacks by militants in Pakistan in recent years but such a high number of police casualties in a single incident is rare. Security forces often carry out operations against bandits in Punjab and in the southern Sindh province, where they hide in rural, forested areas. They have killed several police officers in attacks in recent months. The Kacha area of Rahim Yar Khan district where the attack took place is known to have robbers’ hideouts along the Indus River, where hundreds of heavily armed bandits evade police. Police said one of the police vehicles apparently broke down while passing through accumulated rainwater along farm fields, when dozens of bandits launched the attack. Pakistan has been lashed by monsoon rains since July. Authorities swiftly condemned the attack, one of the deadliest on police in recent years. The president, Asif Ali Zardari, prime minister, Shehbaz Sharif, and interior minister, Mohsin Naqvi, released statements denouncing it, expressing sorrow and describing the slain officers as martyrs. Police were ordered to take immediate action against the attackers and Sharif demanded the best medical care for the wounded officers. Earlier on Thursday, gunmen opened fire on a school van in Punjab, killing two children and wounding six other people, police said. No one claimed responsibility for that attack.