Kenya military reports success in fight for Somali port September 29, 2012 -- Updated 1423 GMT (2223 HKT) The Kenya Defense Forces says it has killed two militant commanders Kenya's leaders congratulate the military on capturing the city Al-Shabaab says it closed its Kismayo offices, but vows to fight The militant group has long tried to overthrow the Somali government Nairobi, Kenya (CNN) -- Kenya's military said its troops killed two commanders of an al Qaeda-linked militant group in neighboring Somalia on Saturday as the troops continued their push into the port city of Kismayo, one of the group's last strongholds. Late-morning airstrikes by the Kenya Defense Forces killed Sheikhs Hassan Yakub and Abdikarim Adow, two key regional commanders with Al-Shabaab, the military wrote on Twitter. Five other Al-Shabaab militants were "neutralized," the military wrote on Twitter, and a truck and assortment of weapons were recovered from a Friday night attack in Kismayo. CNN could not independently confirm the status of Kismayo on Saturday. In a series of posts on a Twitter account often used by Al-Shabaab, the group said it closed its offices in Kismayo late Friday, but it also vowed to make the city a "battle zone" between Muslims and "invaders" and to show it will never be defeated. And already Friday, Kenyan Prime Minister Raila Odinga and Deputy Prime Minister Uhuru Kenyatta used Twitter to congratulate the Kenyan military on its capture of the city. Al-Shabaab is an Islamic group that has long tried to overthrow the Somali government, but it has suffered setbacks in the past year as troops from the African Union launched an offensive to drive them out. The group lost control of much of the capital, Mogadishu, last year. That made Kismayo even more critical to Al-Shabaab, which uses the port to profit from the illegal charcoal trade and smuggling operations. The Kenya Defense Forces, which makes up the majority of troops in the African Union offensive, urged Kismayo residents in a Twitter post Saturday to stay calm and not panic. Thousands of civilians fled the city this month as fighting loomed, according to the U.N. refugee agency. The Kenyan military said last week it was using land, sea and air forces to attack Al-Shabaab and degrade its forces before the offensive on Kismayo.