Three American soldiers have been injured in heavy gunfire with Taliban militants in Afghanistan ' s eastern province of Wardak,Press TVreports.According to local officials, the gunfire erupted between the Taliban and American forces in Saeed Abad district of Maidan Wardak province on Friday. Five Taliban militants were also killed in the fighting. Saeed Abad is a very dangerous area where most US military convoys as well as their supply trucks are being attacked by the Taliban there. Attacks on foreign troops have increased recently as Taliban militants have announced the beginning of their spring offensive across Afghanistan. The militant group said it would use "every possible tactic" to inflict casualties on Afghan and US-led forces, specifically mentioning insider and bomb attacks. The rising death toll of US-led foreign forces in Afghanistan has also prompted growing opposition to the Afghan war in NATO member states and other countries that have contributed troops to the military occupation. On Friday, the commander of the International Security Assistance Force (ISAF) in Afghanistan said that the gains made during about 12 years of war are not yet sustainable. US General Joseph Dunford made the remarks during a meeting on Friday in Kabul with a group of foreign correspondents based in the Afghan capital. He asked the international community not to abandon Afghanistan after foreign forces occupying the country leave next year. "The gains that we have made to date are not going to be sustainable without continued international commitment," Dunford stated. "We are not where we need to be yet". "The continued presence of the international community politically, in development and in security is necessary to sustain the progress that we have made. "Is the effort we have had to date sustainable? I would say no, not until we develop the procedures (and) the institutions necessary to sustain a modern national army."