Japan's Asahi newspaper quoted embassy officials as saying that Yamaji crossed into Myanmar by boat along a river on the border with Thailand.
"Toru Yamaji should be released immediately and allowed to continue covering Burma's elections," said Bob Dietz, CPJ's Asia program coordinator. "Burma, which is one of the most censored countries in the world, has not allowed the foreign media to cover this election. Elections need the scrutiny of a free media to be credible."
Exile groups said the elections were not free and fair, and were an attempt by the military government running the country for more than 20 years to legitimize its hold on power. The U.K. Guadian reported that foreign journalists and monitors were banned from Burma, also known as Myanmar, in the run-up to the polls.
In September 2007, video journalist Kenji Nagai, who also worked for APF, was shot and killed while covering demonstrations by Buddhist monks and their supporters in Rangoon.
CPJ research shows that Burma has at least 12 journalists behind bars.