Somalia's government has launched an investigation after a punch-up in the parliament in the capital, Mogadishu, over the election of a new speaker. Punches were thrown, MPs hit each other with chairs, some used pens to stab one another. Three were taken to hospital. A new speaker was eventually voted in late on Wednesday, but the president has since denounced the election. Somalia's interim government has international backing, but has faced criticism for its factional infighting. With the help of African Union peacekeepers, it now controls Mogadishu but al-Shabab, which has links to al-Qaeda, runs many central and southern areas of the country. The country has been convulsed by war for two decades and has not had a functioning elected national government since 1991.