Magadishu -The al-Shabab extremist group attacked a Kenyan military base inside Somalia with a car bomb and machine guns early on Friday, and both the insurgents and Kenya's military claimed dozens of deaths on the opposite side.Nine soldiers - two officers and seven servicemen - were killed and more than 70 al-Shabaab extremists died in the base attack, Colonel Paul Njuguna, the Kenyan military spokesperson, said in a statement.Two Kenyan police officers also were killed and four seriously wounded when their vehicle struck an improvised explosive device while they were crossing into Somalia to respond to the attack, a Kenyan official said.The official spoke on condition of anonymity because he was not authorized to share the information.Al-Shabaab spokesperson Sheikh Abdiaziz Abu-Musab said the group's fighters killed at least 51 Kenyan soldiers during the early morning attack in Kulbiyow town in Lower Jubba region. But Kenyan military spokesperson Njuguna denied it, saying "scores" of the extremist fighters were killed instead when soldiers repelled the assault.A Somali military officer, Colonel Ahmed Ali, said al-Shabaab used a massive suicide car bomb to penetrate the camp, part of the African Union peacekeeping mission in Somalia, allowing dozens of extremists with machine guns to overrun the base, torching tents and arms depots.Ali also disputed al-Shabab's claim of killing dozens of soldiers, saying the Kenyans fought back before retreating to a nearby area. He declined to give further details.Al-Qaeda's East African affiliate is fighting to impose a strict version of Islam in this Horn of Africa nation. It has lashed out with deadly attacks against countries like neighboring Kenya that contribute to the African Union mission.In February 2016, Kenya tried to downplay a similar al-Shabaab attack that Somalia's president said killed at least 180 Kenyan soldiers. Kenya's military spokesperson denied the figure, but refused to give an official death toll. That attack was considered the bloodiest by al-Shabaab militants to date and Kenya's heaviest military defeat.Thousands of the African Union troops are in Somalia to bolster the country's weak government, while al-Shabaab continues to launch deadly guerrilla attacks like this week's assault on a hotel in the capital, Mogadishu, that killed at least 26.Earlier this month, the AU's Peace and Security Council decided to ask the UN Security Council to authorize a six-month "surge" of 4 500 troops to expand offensive operations. The Security Council was expected to discuss Somalia on Friday.Somalia's security forces are supposed to be taking on more responsibility as the AU force prepares to withdraw by the end of 2020. But concerns remain high about the country's security, and the ongoing al-Shabaab attacks in the capital and elsewhere have contributed to several delays in Somalia's upcoming presidential elections, a key step in the country's recovery.The vote once set for last year is now expected to be held February 8 as the impoverished country tries to recover from decades of chaos that began in 1991, when warlords overthrew a longtime dictator.