KABUL (Agencies) - Britain's Prime Minister Gordon Brown Saturday paid a surprise visit to Afghanistan, where he spoke to troops battling the Taliban and held talks with President Hamid Karzai. The visit came as government and military sources speaking on condition of anonymity said around 300 British soldiers had been deployed from Cyprus as part of an increase in troop levels ahead of next year's presidential election. Brown condemned Friday's 'terrible' killing of British soldiers in Afghanistan, and said that other nations must also send more troops in support of the plan. He said the world could not rely only on the two biggest contributors, Britain and the United States, whose president-elect Barack Obama has said he will send more troops to Afghanistan. Britain's military is feeling the pinch as it fights on two major fronts - in Afghanistan, where it has more than 8,000 troops as part of the NATO-led ISAF, and Iraq. "In future, there must be proper burden sharing and that's something which we will insist upon," he said at a Kabul press conference with Karzai. "As we look forward with president Obama's plans now about to come forward, then burden sharing is very much a part of that." Brown said he was in Afghanistan to "take stock" of the situation. He announced 10 million dollars in funding to encourage registration in the election and said a taskforce of British officials had been offered to Afghanistan to root out corruption. He also called on Pakistan and Afghanistan to work together to ensure cross-border stability in the mountainous area seen as a militants' hideout between the two nations. "Joint action between Pakistan and Afghanistan... is essential if we're going to have peace and stability," he said. Brown started his visit to Afghanistan in Camp Bastion, the huge British military base in southern Helmand province, where he spoke out against two fatal incidents Friday. "It is a terrible commentary on the Taliban that they should use a 13-year-old child as a suicide bomber," he said, referring to one attack which killed three and involved a teenager with a bomb hidden in a wheelbarrow. "There is disgust and horror at these tactics being used by the Taliban," he added. He later took a helicopter to the Roshan observation post near Musa Qala, near where the troops died and a stone's throw from where Taliban fighting has been taking place, and met Gurkha soldiers serving there. Officials said the trip took him right up to the front line, with one claiming he got closer to fighting than any British premier since World War-II leader Winston Churchill. Brown also met acting district governor Said Agha and the local chief of police before returning to Camp Bastion for a meeting with Helmand governor Gulab Mangal covering next year's elections, counter-narcotics and security. The British prime minister left Kabul late Saturday, bound for New Delhi. A government source said Britain was set to confirm Monday that the troop reinforcements ahead of the elections had been carried out in the last few weeks. A military source added they would be trying to secure prime agricultural and poppy-growing land in Helmand alongside other nations including Denmark and Estonia. Meanwhile, Gordon Brown arrived in India late Saturday ahead of talks with his Indian counterpart Manmohan Singh following last month's attacks on Mumbai which killed 172 people. Brown touched down at New Delhi's Indira Gandhi international airport after flying from Kabul, where he met Afghan President Hamid Karzai. He was due to hold talks with Singh at 0830 local time Sunday, an AFP correspondent travelling with him said. He is also expected to review bilateral ties with the Indian leadership before embarking on a four-hour visit to Pakistan on Sunday. In Pakistan, he will meet President Asif Ali Zardari. According to diplomatic sources, he would be telling the leaders of India and Pakistan that they stand to lose a lot from the renewed tension and that the Mumbai incident indicates that both of them share the threat posed by global terrorism.