The head of Britain's security services has said al-Qaida plots targeting Britain are increasingly originating from Somalia and Yemen. He described Somalia as a "seedbed for terrorism" and said it resembles Afghanistan during the 1990s. Jonathon Evans, director-general of Britain's domestic security services, MI5 said Britain's counter-terrorism strategies are getting better but the risk of lethal terror attacks remains. ? Speaking Thursday evening to security industry professionals, Evans said that the nature of the threat is evolving. Just a few years ago, he said, 75 percent of suspected terror threats were originating from northwest Pakistan, but today that percentage has dropped to 50 percent. Now, he said, the threat to Britain's security is increasingly coming from elsewhere, namely from the African countries Yemen and Somalia. Wyn Rees, Professor of International Security at Britain's University of Nottingham, agrees. "By fighting against and driving al-Qaida out of a country like Afghanistan, it has effectively spread, it's been weakened, but it has gone to other parts of the world," said Rees. Security professionals have paid increasing attention to Yemen since a failed bomb plot on a U.S.-bound plane in December last year. Rees says conflict-ridden Somalia is also a ripe breeding ground for terrorism. The country has not had a functioning central government since the early 1990s. The U.N.-backed transitional government has been battling the militant group al-Shabab for the past three years. Rees says the security threat posed by al-Shabab, which is allied with al-Qaida, goes beyond Somalia's borders. "They are effectively an armed group within the country who are willing to train foreign jihadist as part of their own struggle and also perhaps for those people to go back to western countries afterwards to conduct terrorist actions subsequently," added Rees. In his speech, Evans said it's only a matter of time before militants now fighting alongside al-Shabab bring terror to the streets of Britain. He said defending Britain against a terror threat during the 2012 Olympics will be a major challenge.