Chadian rebels mounting what they say is a new offensive against President Idriss Deby advanced deeper into the country from the east on Sunday, briefly occupying the town of Am-Dam, rebel spokesmen said.
Another rebel column attacked the eastern town of Goz-Beida on Saturday, engaging government troops in heavy fighting before pulling back towards the Sudanese border 70 km (40 miles) away.
Oil-producing Chad and Sudan accuse each other of backing insurgents who have attacked both capitals this year.
"We occupied the town of Am-Dam this morning ... We did not meet much resistance," Ali Gadaye, spokesman for the rebel National Alliance, told Reuters by satellite phone.
"We have just left Am-Dam town. We are carrying on."
Am-Dam is a small town about 120 km (75 miles) northwest of Goz-Beida. It is 700 km (440 miles) by road from the western capital N'Djamena, which rebels last attacked in February.
Abderaman Koulamallah, whose Union for Democratic Change (UDC) is part of the National Alliance, told Reuters by phone from France that one rebel column was just west of Am-Dam.
The separate column that attacked Goz-Beida pulled out of the town after fighting with government forces on Saturday but was still in the area, he said. A Reuters reporter saw that column numbered up to 100 vehicles before that attack.
There was no independent confirmation of the rebels' location. Koulamallah said government forces had now taken up positions on the main road to N'Djamena. "We could run up against them in the coming hours or days," he said.
But David Buchbinder, a researcher for U.S.-based Human Rights Watch, told Reuters in Goz-Beida that a repeat of the rebels' February march on N'Djamena was improbable.
