Tirana, Albania (CNN) -- At least three protesters were shot dead from close range in a clash with police Friday outside the Albanian prime minster's office, a hospital official said, an escalation of some of the worst politically fueled tension to wrack the southern European nation in 14 years.

The face-off also left 23 demonstrators hurt, including three in critical condition with head injuries at Tirana Military Hospital, according to its emergency unit chief, Sami Koceku. He said that at least 17 police officers also injured in the confrontations were at that hospital, one of the city's main medical facilities.

A report from state-run network TVSH had a slightly higher injury toll from hospitals throughout Tirana, Albania's capital and most populated city. It put the count at 35 demonstrators and 27 police.

The opposition Socialist Party claimed, on its website, that around 250,000 people gathered outside Prime Minister Sali Berisha's office to implore him to resign amid allegations of corruption and fraud related to the June 2009 election.

Some of the protesters threw stones and Molotov cocktails at some of the more than 1,000 police who were at the scene, ostensibly to provide security. Authorities responded by using water cannons in an attempt to disperse the crowds.

Afterwards, Albania's current president, Bamir Topi, issued a statement urging all political parties to resume talks soon and not to reopen old wounds -- referring to a 1997 at-times violent crisis that also targeted Berisha, who was then the nation's president.

Topi urged "calm and self-restraint" by all Albanians, as well as support for the police and governmental institutions.

The U.S. Embassy in Tirana issued a like-minded statement on Friday, expressing "deep regret that (the protest) was not peaceful" and calling on all sides "to abstain from provocations." Rather, the embassy pushed for "constructive dialogue and compromise to resolve the existing political differences."

And the European Union, which has been considering adding Albania as a member, also "urgently" appealed to "all political forces ... to engage in a constructive (dialogue) and to mobilize the countries' energies" to resolve the political stalemate.

"Demonstrators are instruments of freedom of expression and peaceful assembly for citizens," said EU foreign policy chief Catherine Ashton and Stefan Fule, commissioner for enlargement and the European neighborhood policy, in a statement. "We deplore that today's event has spiralled into violence."

Yet key players in Friday's incident, and in the long-brewing political friction in Albania, showed no signs of backing down Friday.

Berisha directly blamed the casualties on his chief political rival, Socialist Party leader Edi Rama, whom he accused of scheming to have demonstrators take over the prime minister's office, parliament and key ministries, state-run ATA news agency reported.

Rama "will take full responsibility," Berisha told reporters, adding that Friday's actions "will not be accepted, but punished."

For his part, Rama -- who is also the mayor of Tirana -- accused government forces of going overboard, and blamed police for provoking protesters by using the water tanks and tear gas.

Earlier this month, in an interview quoted in a Socialist Party newsletter, Rama reiterated long-standing claims that Berisha's ruling Democratic Party had rigged the most recent election.

"Are there any Albanians who have not yet understood that (Berisha) stole the elections in order to rob Albania?" he said. "That was clear to us from the very beginning, but by now it has become clear to every reasonable Albanian."

The country's supreme court determined that the elections were orderly, and the ballots were burned by the Central Election Commission.

The Socialist Party boycotted Albania's parliament between September 2009 and February 2010, according to the U.S. State Department.

Efforts since then to resolve the long political stalemate have been unsuccessful, with opposition parties continuing to push hard against the Democrats in alleging corruption.

On Friday, Berisha guaranteed that there would "be no early elections" and that "general elections will be held in 2013," a rebuttal to the timeline being pushed by the opposition.

The tensions escalated in the past two weeks, after a former government minister sent the media a secret recording that allegedly documented an illicit back-room deal.

In the video, then-Deputy Prime Minister Ilir Meta asked Dritan Prifti, who at that point was Albania's economic minister, to arrange for irregular contracts and have the government hire hacks who belonged to his small party, the Socialist Movement for Integration.

Meta later replaced Prifti, a member of that same party, as economic minister. He resigned from that position last week, even as he claimed that the tape featuring him and Prifti had been manipulated with bits edited in and out, out of context.

Still, the opposition largely has focused its wrath on Berisha.

This is not his first time under fire: In 1997, for instance, angry mobs protested against Berisha -- then the nation's president -- after voting irregularities and costly Ponzi schemes plunged Albania into near-anarchy and led to snap elections.

The animosity, and harsh rhetoric, have heightened in recent weeks. In addition to increasingly pointed, accusatory barbs between Rama and Berisha, personal slurs marred a parliamentary session this week meant to settle governmental changes following Meta's resignation.