After less than a year in power, embattled Prime Minister Shinzo Abe said Wednesday he intended to step down to clear the political gridlock created by the ruling coalition's defeat in the House of Councilors in July and to expedite the extension of the controversial antiterrorism law.

"I have decided today that I should step down as prime minister," Abe told a hastily arranged news conference in the afternoon. "It is extremely important to continue the fight against terrorism. It is my promise and it is my international pledge. To carry out the task, I decided that it is necessary for me to step down and change the situation."

The surprise announcement came just three days after Abe said he was ready to resign if he failed to extend the Maritime Self-Defense Force's refueling mission in the Indian Ocean to continue Japan's support for NATO-led counterterrorism operations in Afghanistan.