LONDON - British Prime Minister Gordon Brown will defend his government’s commitment to Afghanistan in a major speech today, saying the war is essential to his country’s security, according to excerpts released in advance by his office.

The speech comes after the deaths of seven British soldiers in the past week, including five who were shot and killed by an Afghan police officer they were training. Despite increasing doubt over the country’s involvement in the war in Afghanistan, Brown links military action there to safety on Britain’s streets. U.S. President Obama still is mulling the level of U.S. involvement in Afghanistan, although he is believed to favor some kind of troop increase.