China protested to Indonesia for letting Taiwanese President Chen Shui-bian stop in the country on his way back from a visit to Latin America, a statement said Friday.
Beijing made "serious representations" to Jakarta after Chen's one-night stop in the resort island of Batam, the statement on the foreign ministry's website said.
"We demand Indonesia take practical action to fulfill its commitment to the one-China policy in order to maintain the overall friendly Sino-Indonesian relations," Chinese foreign ministry spokesman Liu Jianchao said in the statement.
China regards Taiwan as part of its territory, despite it being ruled separately since the end of a civil war in 1949, and opposes any overseas visits by Taiwan leaders.
The Indonesian government on Friday expressed its regret over the stopover, saying it only gave Chen permission to refuel and had not expected he would leave the airport.
"The permit that was given was for a technical landing because there was some trouble," Foreign Minister Hassan Wirayuda told reporters on the Indonesian resort island of Bali.
"We regret that," he said of the fact that the president had left the airport and traveled around the island of Batam, where his flight landed. "That was an abuse of the permit that was given," he added.
Jakarta recognizes Beijing, rather than Taipei, which is on a constant diplomatic battle to maintain diplomatic ties with its dwindling number of allies — now just 25 — and sign up more supporters.
Indonesia's senior security minister Widodo Adisucipto told reporters his country adhered to the one-China policy, under which Beijing defines Taiwan as a part of China.
He said that Indonesia's President Susilo Bambang Yudhoyono had asked for a report from the governor of Riau province, where Batam island is located, on the incident.
Chen returned home Friday to a welcome from his supporters.