ADDIS ABABA, Oct 7, 2008 (AFP) - Mauritania's military junta met top African Union officials in Addis Ababa on Tuesday, a day after an AU deadline for reinstating the ousted president passed unheeded.

The eight-man delegation held talks with the pan-African body's top executive, Jean Ping, even as opposition protesters were set to defy a ban on demonstrations in the Mauritanian capital, Nouakchott.

No details on the nature of the discussions were immediately available.

'The delegation arrived yesterday (Monday) in Addis Ababa. It is led by Justice Minister Tidjane Bal and consists of several key officials, including a foreign ministry official in charge of African affairs,' Assane Ba, spokesman for the AU's peace and security council, told AFP.

The military junta, led by General Mohamed Ould Abdel Aziz, had largely ignored an October 6 deadline set by the African bloc for the 'return of constitutional order' in the west African country.

The junta ousted Sidi Ould Cheikh Abdallahi, the country's first democratically elected president, on August 6.

The African Union has threatened to impose sanctions, and opponents of the junta in the country had called Monday for the bloc to make good on its threat against the junta.

'We demand the immediate implementation of sanctions against the junta, in line with the ultimatum set by the AU if the military does not give up power,' said Mohamed Ould Mouloud, a spokesman for the National Front for the Defence of Democracy, a coalition of five anti-coup parties.

The Front later announced plans to hold a march at 4 pm (1600 GMT) on Tuesday in Nouakchott despite a continued ban on demonstrations to keep up pressure on the junta.

On Sunday riot police used tear gas to disperse several small protests by supporters of the ousted president.

According to the anti-coup movement, the junta has begun an 'escalation of repression against all political opposition.'

In Nouakchott, politicians backing the military coup shrugged off the AU ultimatum.

'We don't care about these ultimatums, this doesn't scare anybody,' said Sidi Mohamed Ould Maham, a spokesman for the majority of members of parliament who support the new military leadership.

Speaking to AFP late Monday, an anonymous AU official said, 'The AU would maintain and reiterate its position on the return of constitutional law in Mauritania.'

The sanctions could take the shape of travel restrictions and asset freezes such as those the AU imposed in the Comoros isle of Anjouan on Mohamed Bacar, the renegade leader who was ousted by AU forces earlier this year, officials have said.

The continental body has also been pushing for the release of the ousted Mauritanian president. The army says he has been kept under house arrest but his daughter says his whereabouts are unknown.

Abdallahi was ousted hours after he issued a decree firing the Mauritanian military's top brass, including Abdel Aziz, who was the commander of the presidential guard.

Since the coup, the junta has taken over the powers of the president and formed a new government with the support of a majority of the deputies in parliament.

The new leadership has promised to hold elections quickly, but no date has been set and parliament has voted to delay a presidential vote by at least a year.