MAZAR-E SHARIF, Afghanistan -- The Afghan government has announced a day of mourning in the wake of an April 21 attack by the Taliban on a military compound in Balkh Province that officials say left more than 130 army personnel dead.



President Ashraf Ghani's office said in a statement that flags across the country would be flown at half-staff on April 23 following the deadly assault in Mazar-e Sharif that officials say was carried out by militants dressed in Afghan Army uniforms.



Ghani's acting spokesman, Shah Hussain Murtazawi, told RFE/RL's Radio Free Afghanistan in a telephone interview from Kabul that Ghani announced the national mourning "in order to pay tribute to the martyrs of Friday's attack."



Afghan Defense Ministry spokesman Daulat Waziri said on April 22 that two of the 10 attackers carried out suicide bombings during the assault, while the other eight were shot dead during the ensuing gunbattle.



The ministry said that more than 100 military personnel were killed or injured in the attack.



But officials in Kabul told Radio Free Afghanistan that more than 130 had been killed, and a high-ranking military official in Mazar-e Sharif put the figure at 138. Officials said the death toll could rise.



The Defense Ministry said it is investigating the exact number of those killed and injured in the attack. It said it would announce the final numbers to the nation but did not indicate when such an announcement might come.



Waziri, the ministry spokesman, said that the victims were almost all members of the 209th Corps of the Afghan National Army (ANA).



The Taliban claimed responsibility for the attack, saying that more than 500 Afghan soldiers had been killed or wounded. The Taliban statement also said four of the attackers were soldiers who had been stationed at the outpost.



The attack targeted a mosque where soldiers were at Friday Prayers, as well as a dining hall.



Ismael, an Afghan Army soldier who witnessed the assault, told Radio Free Afghanistan that he was baffled at how the assailants managed to penetrate the military compound, and that the attack "will make people have second thoughts about joining the ANA."



"If [the militants] could enter the army base today, they probably could do something bigger at another time," he said, adding that he was "in a state of confusion and shock."



German Chancellor Angela Merkel offered condolences to Afghanistan, saying she was horrified by "the Taliban's deceitful, brutal barracks attack on your soldiers."



"My sympathy to the many injured and the relatives of the many victims," she wrote in a telegram to Ghani.



A German Army contingent is stationed at the base, which serves as the Afghan Army command center in the north of the country.



In an April 21 statement following the attack, U.S. General John Nicholson, commander of NATO's Resolute Support operation, praised "the Afghan commandos who brought today's atrocity to an end."

With reporting by AP, AFP, and dpa