Large contingents of Iranian security personnel brandished clubs, fired shots into the air and used tear gas to force back hundreds of people who, defying the regime's calls for a halt to protests, gathered outside parliament on Wednesday. Armored vehicles moved in to arrest the demonstrators, "shoving them in like livestock," according to a source in Teheran. Mir Hossein Mousavi, the defeated presidential candidate who says the June 12 vote was rigged, has not been seen since last Thursday and is widely believed to be in hiding. But the protests were organized through his official Web site, and he has previously sent messages urging the demonstrators to continue their rallies. In a message on another site, Mousavi's wife, Zahra Rahnavard, also urged protesters to fight on. She compared the regime's crackdown to martial law. Wednesday's protests were small when compared to the massive ones in the first days after incumbent President Mahmoud Ahmadinejad was proclaimed the election winner, with many opposition supporters now intimidated by the regime's ruthless response. The official death toll is 17, but unofficial sources say the true number is far higher. From the rooftops and windows of Teheran apartment buildings, however, residents are keeping up their protest slogans, with reports Wednesday of shouts of "Death to the Islamic Republic." One witness said the parliament area was swarming with hundreds of riot police, who were trying to prevent people from gathering even briefly. Thousands more security officers filled the surrounding streets. "The demonstration was supposed to be peaceful," a contact in Teheran told this reporter. "But the Basiji [militiamen] beat people down like animals." He said the son of one of his employees, who participated in the rally, compared the scene to the frontlines of a war: "It was like they were beating up dolls. The security forces were out for blood. Hundreds of them charged out of nowhere. The next thing we saw was fire, blood, and clouds of tear gas," he reported. With Mousavi out of view, and all prominent reformist figures under arrest or also in hiding, the opposition had no visible leadership, another source said. Protesters are now taking off their pro-Mousavi green wrist bands, so as not to attract the attention of the security forces. "The city is on lockdown, and we are like sheep ready to be slaughtered," said one Teherani in a brief telephone interview. "It is important for us to be prepared and to have protection," he added, implying an effort to obtain arms. "Anyway, 40 days from Saturday's bloodshed" - a key symbolic day of mourning - "we will be ready." In a statement released on Wednesday, Iran's Press TV said police had raided a building in central Teheran that was being used as a "headquarters" to foment post-election unrest. The television station, citing unnamed sources, said the building was used by members of the opposition as a "networking" center with ties to "foreign elements." Iranian authorities said they had arrested several foreign nationals, some with British passports, for encouraging the protests. Intelligence Minister Gholamhossein Mohseni-Ezhei repeated accusations that the West and Israel had planned a series of bombings in Iran ahead of the elections. And while Supreme Leader Ali Khamenei again discounted any notion of political compromise, authorities were reported in state-run media as saying that Neda Soltani, 27, the protester who was slain on Saturday and has emerged as an emblem of the government's crackdown, might have been killed "by mistake." On Wednesday, smoldering embers of candles were visible on a street corner in central Teheran, from a vigil held the night before for the young woman, seen bleeding to death from gunshot wounds in footage screened around the world since last weekend. Rahnavard, a former university dean who campaigned alongside her husband, said his followers had the constitutional right to protest and that the government should not deal with them "as if martial law has been imposed in the streets." She called for the release of all activists and others arrested at protests. Mousavi, a former prime minister, saw his campaign transform into a protest movement after the government declared that Ahmadinejad had won the election. Western analysts who have examined available data on the vote have tentatively endorsed his allegations of fraud. Khamenei has ordered protests to end, leaving Mousavi with the choice of restraining followers or continuing to directly challenge the country's ultimate authority despite threats of escalating force. "On the current situation, I was insisting and will insist on implementation of the law. That means, we will not go one step beyond the law," Khamenei said on state television. "For sure, neither the system nor the people will yield to pressure at any price." He used language that indicated he was referring to domestic pressures. Khamenei told opposition supporters once again to halt their protests and accused the US, Britain and other foreign powers of fomenting the unprecedented street protests over the vote. Meanwhile Wednesday, a conservative candidate in the disputed election said he was withdrawing his complaints about voting fraud for the sake of the country, state television reported. The announcement by Mohsen Rezaie, a former commander of the Revolutionary Guards, moved the cleric-led government one step closer to a final declaration of victory for Ahmadinejad. State TV reported that Ahmadinejad would be sworn in sometime between July 26 and August 19. Iran also said that it was considering downgrading ties with Britain, which it has directly accused of espionage in recent days. The government accused Britain of using spies to foment the protests and Iran expelled two UK diplomats on Tuesday. British Prime Minister Gordon Brown announced that two Iranian diplomats were being sent home in retaliation. Foreign Minister Manouchehr Mottaki was asked about the option of reducing the level of diplomatic relations with London after a cabinet meeting in Teheran. "We are studying it," Mottaki said, according to state television. Another opposition figure, reformist presidential candidate Mahdi Karroubi, has called for a day of mourning on Thursday for those killed in protests since the election. But Saeed Razavi, the spokesman for Karroubi's campaign, said on the candidate's official Web site later that any mourning was canceled because authorities hadn't given permission. He said the mourning would be conducted next week at the University of Teheran or near where those slain were buried. Also, a Mousavi aide confirmed that police had raided offices of a newspaper owned by the candidate and detained 25 editorial employees. Ali Reza Beheshti said the raid took place on Monday evening in central Teheran as editorial personnel were preparing to relaunch the newspaper, Kalemeh Sabz, or the Green Word. The paper had been absent from newsstands for more than a week. "Police in uniform raided the office and detained 25 members of the editorial staff," Beheshti said. Amnesty International said on Wednesday it was concerned that arrested demonstrators were at risk of torture or other ill treatment. It urged Iranian authorities to give the detainees access to their families, lawyers and any medical treatment they might need. "Anyone detained solely for their peaceful expression of their views regarding the outcome of the election should be released immediately and unconditionally," it said. Two players on Iran's national soccer team, Mehdi Mahdavikia and Ali Karimi, resigned for personal reasons, the semi-official ISNA news agency reported. The pair were among several team members who wore green wrist bands - the color of Mousavi's opposition movement - before a World Cup qualifying match played last week against South Korea in Seoul.