Ibn Saud's ambition to extend his authority beyond the Nejd to al-Hasa provoked opposition.
When Ibn Saud took Hofuf, the Al Ajman, a Khatani tribe living on the Summan plateau between Riyadh and the eastern coast, could see that, unless they took action, their days of independence were numbered.
When Ibn Saud called upon the support of the Ajman at the battle of Jarrab, their performance had been desultory. Indeed Ibn Saud was convinced that, at a crucial moment in the battle, they had betrayed him.
The Al Saud forces attacked the Ajman as they rested in a palm grove at Kinzan, some 20 miles west of Hofuf. Although taken by surprise, the Ajman fought back ferociously, neither seeking nor giving any quarter. Those of Ibn Saud's men who were not killed were forced to retreat to Hofuf, leaving the rest of al-Hasa in the control of the victorious Al Ajman.
Ibn Saud was effectively cut off in Hofuf from the Nejd and, had it not been for the timely assistance of his brother Muhammad, and Salim, the son of the Kuwaiti Sheikh Mubarak, who led forces to his aid, Ibn Saud could well have found himself trapped.