Nepali police fired tear-gas Saturday to stop pro-democracy demonstrators from pushing through a security cordon near the royal palace.
The protesters, marching for the 17th straight day, defied a curfew and shoot-on-sight orders issued to police. This was the first time they reached the center of the capital.
As they marched, leaders of an alliance of political parties formally rejected an offer by King Gyanendra to allow the formation of an interim government. Opposition politician Minendra Rijal says this was done partly to prevent violence.
"If people get the feeling that political parties have let them down, if they feel like we left them mid-stream, they might turn violent," he said.
The opposition has been demanding a full return to democracy, which the king suspended 15 months ago.
Nepal has been mired in political deadlock since King Gyanendra took control of the government. He says he had to act, because the parties failed to bring stability to the country, which is battling a communist insurgency.
The king had stood firm until Friday, when he reversed his position in a televised address. He called on the opposition coalition to suggest an interim prime minister, who would head a council of ministers to rule Nepal, until parliamentary elections could be held next year.
While protesters and the political alliance rejected the offer as too little too late, the offer won praise from India and the European Union. Finnish Charge d'Affaires Pauli Mustonen was among three EU ambassadors to Nepal to meet with opposition party leaders Saturday.
"We have expressed that we hope that this would lead to a process that would provide an end to the violence and a restoration of full democracy and dialogue for peace," he said. "Our visit today was to promote that objective."
Opposition parties are demanding the immediate restoration of parliament.