SANAA, Yemen (AP) -- Authorities flooded the streets of Yemen's capital with 2,000 police Wednesday to try to halt six days of Egypt-style demonstrations against the president of 32 years, a key U.S. ally in battling al-Qaida. One person was killed when police and protesters clashed in the southern port of Aden in the first known death during Yemen's political unrest.

The police, including plainclothes officers, fired in the air and blocked thousands of students at Sanaa University from joining thousands of other protesters in the capital of the Arab world's most impoverished nation.

A call spread via Facebook and Twitter urging Yemenis to join a series of "One Million People" rallies on a so-called "Friday of Rage" in all Yemeni cities, seeking the ouster of President Ali Abdullah Saleh.

"We will remain in the streets until the regime departure," according to a statement posted on Facebook. Copies signed by a group named the Feb. 24 Movement were distributed among youth via e-mail. The group is taking that name because organizers hope to have their biggest protest on that day next week.

Taking inspiration from the toppling of autocratic leaders in Egypt and Tunisia, the protesters are demanding political reforms and Saleh's resignation, complaining of poverty, unemployment and corruption.

Saleh has tried to defuse protesters' anger amid the unprecedented street demonstrations by saying he will not run for another term in 2013 and that he will not seek to set up his son, Ahmed, to succeed him in the conflict-ridden and impoverished nation.

Protesters still chanted slogans against the president's son Wednesday.

Saleh has become a key U.S. partner in battling al-Qaida in the Arabian Peninsula, the terrorist network's offshoot in Yemen. The group's several hundred fighters have battled Saleh's U.S.-backed forces and have been linked to attacks beyond Yemen's borders, including the failed attempt to blow up a Detroit-bound airliner in December 2009. The U.S. military plans a $75 million training program with Yemen's counterterrorism unit to expand its size and capabilities in the nation's mountainous terrain.

It's a difficult balancing act for Saleh, who has been criticized as being too close to the United States.

Yemeni state TV reported that Saleh has been holding meetings since Sunday with heads of tribes to prevent them from joining the anti-government protests.

Witnesses said police chained Saana University's iron gates in order to prevent students from streaming into adjacent streets. They said at least four protesters were wounded in scuffles with police.

Demonstrations also took in the cities of Aden and in Taiz, where thousands shouted, "Down ... down with Ali Abdullah Saleh."

Riot police in Aden fired live ammunition, rubber bullets and tear gas in fierce clashes with thousands of demonstrators, and a security officer said a 23-year-old protester was killed when he was shot in the head.

Five others were wounded, at least one seriously, according to a medical official, who like the security officer spoke on condition of anonymity because they were not authorized to talk to the media.

The protesters, who included students and workers, set tires ablaze in the Mansoura district, witnesses said. Heavy gunfire rattled residents, and many closed their shops and stay home.

Protesters have been camping in Safir Square in central Taiz, about 270 miles south of Sanaa, saying they will not leave until Saleh steps down. Just like in Cairo's Tahrir Square, protesters have organized a makeshift camp in the city center, with medical teams, cleaning crews and security to protect them from outside attacks, said Ghazi al-Samie, a lawyer and activist.

Al-Samie said thousands have joined the protests in recent days in Yemen's second-biggest city.

About 120 judges held a protest in front of the Ministry of Justice in Sanaa, calling for an independent judiciary and better salaries. It was the first demonstration by judges in Yemen.

Saleh's government is weak - its control barely extends beyond the capital and is dependent on fragile alliances with powerful tribes - and it faces other serious challenges.

For more than six years, government forces have been battling a sporadic armed rebellion in the north. A secessionist movement by once-independent southern Yemen also is heating up.

Yemen's main source of income - oil - could run dry in a decade, and the country is also rapidly running out of water. Much of the population suffers from malnutrition.

Yemen has been the site of anti-U.S. attacks dating back to the 2000 bombing of the USS Cole in Aden harbor, which killed 17 American sailors. Radical U.S.-born cleric Anwar al-Awlaki, thought to be hiding in Yemen, is suspected of having inspired some attacks, including the deadly 2009 shooting rampage at Fort Hood, Texas.