UNITED NATIONS (AFP) -- UN chief Ban Ki-moon urged "maximum restraint" Thursday after Syria and Turkey traded artillery fire across their shared border in a deadly exchange that sent regional tensions soaring.

Turkey demanded strong UN Security Council action after the Syrian fire killed five Turkish women and children Wednesday, but Russian objections stalled action on a resolution condemning Damascus.

"The secretary-general calls on all concerned to abandon the use of violence, exercise maximum restraint and exert all efforts to move toward a political solution," his spokesman Martin Nesirky said.

The incident marked the first time that Turkish civilians -- including a mother and her three children -- have been killed by Syrian fire since the start of an uprising in Syria against President Bashar al-Assad in March 2011.

Turkey retaliated by counter-shelling a Syrian position, reportedly killing several Syrian soldiers. The Syrian ambassador to the United Nations said two Syrian soldiers were wounded.

In calling for restraint, Ban warned of the danger of the conflict in Syria spilling into neighboring states.

"As the situation inside Syria deteriorates yet further... the risks of regional conflict and the threat to international peace and security are also increasing," he said.

The special UN-Arab League envoy on Syria, Lakhdar Brahimi, has been encouraging an easing of tensions in contacts with Turkish and Syrian officials, Nesirky said.

"This cross-border military activity is very destabilizing and must be stopped," US Ambassador to the United Nations Susan Rice said. "We think it is very important that the Security Council speaks clearly and swiftly to condemn this shelling."

But in Washington, State Department spokeswoman Victoria Nuland said the Turkish move was an "appropriate" and "proportional" response to the Syrian shelling, intended to deter future aggression.

Syria's ambassador to the United Nations, meanwhile, said Damascus was not seeking an escalation in tensions with Turkey or other countries.

"The Syrian government has a key interest in maintaining good neighborly relations with Turkey," Ambassador Bashar Jaafari told reporters.

"In case of border incidents between any two neighboring countries, governments should act wisely, rationally and reasonably."

But he called on the Turkish government to cooperate with Syria on controls to "prevent armed groups from infiltrating through this border" to stage attacks in Syria.

In a letter Wednesday to Guatemalan Ambassador Gert Rosenthal, who heads the rotating presidency of the 15-nation council, Ankara's UN Ambassador Ertugrul Apakan urged the panel to take "necessary action" to stop what he called "an act of aggression by Syria against Turkey." 

"It constitutes a flagrant violation of international law as well as a breach of international peace and security. Turkey calls for an immediate end to such unacceptable violations," the letter continued.

A draft Security Council resolution was circulated condemning the Syrian strike "in the strongest terms," and saying the shellings "constitute a serious threat to international peace and security."

It had been set for approval by "silence procedure" early Thursday -- meaning the text would be considered adopted if no country objects -- but "the Russians broke the silence," said Britain Ambassador Mark Lyall Grant, providing no details on Moscow's objections.

A diplomat said Russia wanted to remove a reference to peace and security from the text and insert "amendments that weaken the text and are not acceptable" to the Western powers.

Experts from the 15 countries on the Security Council met to try to find a compromise.

Moscow, a historic ally of Damascus, opposes any military action against the Assad regime and has accused the West of fueling the 18-month conflict by allowing arms to flow to the opposition.

Russian spokesman Alexander Lukashevich had said earlier in Moscow it was "important (that) a balanced approach, based on real facts, is exercised by the UN Security Council."

Moscow's Foreign Minister Sergei Lavrov said Syria told Russia that the strike was a "tragic accident," and said it was "vital that Damascus states this officially."

Germany's UN Ambassador Peter Wittig meanwhile said his government felt it was "important for this council to act responsibly and unified in order to avoid further conflagration."

He recalled that Berlin had "strongly condemned the Syrian shelling and at the same time called for restraint on all sides."