Thousands took to the streets of Honduras Saturday demanding the return of ousted President Manuel Zelaya, as the mediator of the high-stakes talks, Costa Rican President Oscar Arias, called for his reinstatement.

Honduras's military was on alert, watching the demonstrations -- and for a threatened attempt by Zelaya to enter to the Central American country he was thrown out of on June 28 by the army.

US officials had already warned that any attempt by Zelaya to return to Honduras could jeopardize negotiations between representatives of Zelaya and of interim leader Roberto Micheletti, whose de facto government replaced him.

In resuming the talks on Saturday, Zelaya's delegation arrived at Arias's house an hour late, flying in from Guatemala, Nicaragua and elsewhere in Latin America. Micheletti's team was already inside.

Arias was said before the meeting to be pushing for a "government of national reconciliation," and as talks got under way, he proposed Zelaya be reinstated as president over a new government and amnesty for the coup leaders -- notions thoroughly rejected by Micheletti's side.

One diplomatic source involved in the talks however told AFP beforehand: "It's fairly probable we'll have an agreement within 48 hours."

As discussions started, Zelaya supporters in Honduras continued their daily rallies demanding he be restored to power.

For the third day running they blocked roads, including some around the capital Tegucigalpa. Some 2,000 filled a southern boulevard, yelling "What's our president's name? Manuel Zelaya!"

The head of the Human Rights Defense Committee for Honduras, Andres Pavon, said the road to Honduras's second city of San Pedro Sula and to the international airport were cut by the protests.

"Tensions are very high," a US State Department spokesman, Robert Wood, said in Washington.

He warned off any attempt by Zelaya to try to return while the talks were going on.

"We don't want people to take steps that in any way conflict or don't contribute positively to the Arias mediation efforts," Wood said.

Zelaya already made an attempt to return two weeks ago on a Venezuelan jet but was prevented from landing by Honduran military vehicles parked on the runway.

He has called for an insurrection against those now ruling Honduras. While he has sent aides to the talks, he has said he would give them to late Saturday to reach an agreement acceptable to him, and has vowed to return to the presidency.

Although Zelaya describes his ouster as a "coup," Micheletti has fiercely rejected that term.

He and his de facto government instead accuse Zelaya of defying a Supreme Court ruling and ignoring the constitution by trying to hold a referendum without congressional approval.

Many in Honduras believe Zelaya, a wealthy rancher who moved sharply to the left after taking office in January 2006, wanted to rewrite the constitution to lift the one-term presidential limit and stand for reelection this year.

Zelaya's strongest ally, Venezuelan President Hugo Chavez, said the ousted Honduran president would be restored to power.

"Zelaya is going to enter Honduras, let's see what those thugs do," Chavez said, referring to Micheletti government.

Rumors have swirled that Zelaya might try to cross over into Honduras by land from Nicaragua, possibly with Venezuelan or Nicaraguan military units.

Honduras has reinforced military surveillance of the border.

The talks between both sides began last week under Arias's mediation, but quickly arrived at an impasse.

Zelaya and Micheletti left Costa Rica without meeting face-to-face.