* Syrian tanks shell Hama, violence in other cities
* U.N. chief Ban says Security Council sends clear message
* Rights body details further army abuses
BEIRUT, March 22 (Reuters) - Clashes flared across Syria on Thursday, opposition activists said, the day after the U.N. Security Council had called on all sides to stop fighting and seek a negotiated settlement to the year-long uprising.
U.N. Secretary General Ban Ki-moon said the Council's unanimous statement had sent a clear message to Syria to end all violence, but the appeal had little impact on the ground, where rebels are seeking to oust President Bashar al-Assad.
Opposition sources said Syrian tanks had heavily shelled a large neighbourhood in the city of Hama on Thursday after fighting between Free Syrian Army rebels and pro-Assad forces.
The shelling destroyed houses in the Arbaeen neighbourhood of northeast Hama, which has been at the forefront of the revolt. Opposition sources said at least 20 people have died in army attacks in the area in the last two days.
It is impossible to verify reports from Syria because the authorities have denied access to independent journalists.
Syrian troops also attempted to storm the northern town of Sermeen on Thursday, killing one man and wounding dozens, the British-based Syrian Observatory for Human Rights (SOHR) said, quoting its network of contacts within Syria.
"Syrian forces are still not able to get inside the town because of fighting but they are shelling Sermeen and using heavy machine guns," said SOHR head Rami Abdelrahman.
Fighting was likewise reported in the central Hama province and the southern city of Deraa, where several soldiers died in an ambush, and loyalist forces conducted raids in the eastern province of Deir al-Zor, he added.
The Security Council statement, which was supported by both Russia and China, marking a rare moment of global unity over the crisis, backed a peace drive by U.N.-Arab League envoy Kofi Annan and warned of "further steps" if Syria failed to respond.
Annan's six-point peace proposal calls for a ceasefire, political dialogue between the government and opposition, and full access for aid agencies. It also says the army should stop using heavy weapons in populated areas and pull troops back.
FIRING INTO LEBANON
While the U.N. statement, which lacks the legal force of a resolution, talks of the need for political transition in Syria, it does not demand that Assad to step down - something both the rebels and the Arab League have called for.
"In clear and unmistakable terms, the Security Council called for an immediate end to all violence and human rights violations," U.N. chief Ban said in a speech in the Malaysian capital Kuala Lumpur.
Syria's official news agency appeared to play down the Council statement, saying it contained "no warnings or signals".
At least 8,000 people have died in the revolt, according to U.N. figures issued a week ago, and diplomats have warned that without a swift resolution, the conflict could spread and degrade already tense sectarian relations across the region.
Underlining the dangers, several Syrian shells landed in the Lebanese border village of al-Qaa and nearby fields late Wednesday, wounding one person, after heavy artillery was heard on the Syrian side of the frontier, residents said.
"More than five shells landed in the fields and in the village," a farmer in al-Qaa told Reuters. Another resident said one shell had detonated next to the main school.
The Human Rights Watch (HRW) group said on Thursday Syrian security forces were committing "serious abuses" in Qusair, a city in the province of Homs, near the Lebanese border.
"Following their bloody siege of Homs, the Assad forces are applying their same brutal methods in Qusair," said Sarah Leah Whitson, the HRW Middle East director.
"Having seen the devastation inflicted on Homs, the Russian government should stop arms sales to the Syrian government or risk becoming further implicated in human rights violations."
Russia has defended its long-standing military ties with Syria and has said it sees no reason to modify them.
Earlier this week, the New York-based HRW accused opposition forces of committing rights abuses on government troops and their militia allies, including torture and summary execution.
Syrian Foreign Ministry spokesman Jihad Makdissi told Dutch radio on Monday that 3,000 members of the security forces had died in the uprising, which Damascus blames on terrorist gangs.
RUSSIA HEDGING BETS
Looking to pile pressure on Syria, the European Union is set to impose further sanctions on Assad's inner circle on Friday, including his wife Asma, who described herself as "the real dictator" in an apparently genuine email published by Britain's Guardian newspaper last week.
"Tomorrow we will decide on new sanctions, not only against the Assad regime but also against the people around him," German Foreign Minister Guido Westerwelle told Deutschlandfunk radio.
He added that the U.N. statement was an important contribution to solving the crisis in Syria.
"Assad cannot depend on the protective hand of Russia in the violence against his own people and that could accelerate the process of erosion of the regime."
Although Russia has not budged from its main demand that Assad must not be shunted from office by foreign powers, it has adopted a much sterner tone this week, accusing the Syrian leadership of mishandling the crisis.
Analysts say this change of tack is a sign Russia is hedging its bets about Assad's fate and wants as strong a hand as possible in shaping Syria's future should he fall.
"Russia will not be focused on keeping Assad in power for the sake of keeping Assad in power," said Dmitry Trenin, director of the Carnegie Moscow Centre think tank.