US Secretary of Defense James Mattis arrived in Kabul Monday on an unannounced visit on the day that Afghan’s defense minister Abdullah Habibi and Army Chief of Staff Qadam Shah Shahim stepped down after the deadliest Taliban attack on a military base on Friday. The Taliban assault on a base at the northern town of Mazar-i-Sharif left at least 140 National Army Afghan troops dead. Afghan President Ashraf Ghani announced he had replaced the commanders of four army corps after the attack, and defense officials said eight army personnel were arrested, raising suspicions that the attackers had inside help. Mattis will hear a push for more US troops when he meets Afghan officials and US commanders. The Trump administration is currently holding a review on strategy in Afghanistan.