U.N. envoy Kofi Annan on Sunday asked the Damascus regime and the opposition to immediately halt violence and the use of heavy weapons.

"I urge all forces whether governmental, opposition or others to put down their weapons and work with the United Nations monitors to consolidate the fragile cessation of violence in all its forms," Annan said in a statement.

The U.N. Security Council on Saturday threatened the African nation of Guinea-Bissau with "targeted sanctions" if the country's military junta did not step down and return civilians to power.

The Council reiterated its "strong condemnation" of the April 12 military coup, and demanded the "immediate restoration of the constitutional order as well as the reinstatement of the legitimate government of Guinea-Bissau."

The U.N. Security Council on Saturday unanimously passed a resolution allowing a 300-strong ceasefire monitoring mission in Syria despite the strong doubts of many Western nations.

Under U.N. resolution 2043, the unarmed military observers will be sent for an initial period of 90 days if U.N. leader Ban Ki-moon decides it is safe for them to go.

China said Thursday it was considering sending observers to monitor a Syrian ceasefire that came into force last week but is under threat as violence escalates.

"China is earnestly looking into whether to send observers to Syria or not," foreign ministry spokesman Liu Weimin told reporters at a regular briefing.

India on Thursday successfully tested a new long-range missile capable of delivering a one-ton nuclear warhead anywhere in regional military rival China, and countries outside Asia.

The 17-metre (56-foot) Agni V, with a range of more than 5,000 kilometers, was launched at 8:05 (02:35 GMT) from a test site off the eastern state of Orissa, according to the Defense Research and Development Organization (DRDO), which built the missile.

U.N. chief Ban Ki-moon has called for an expanded U.N. ceasefire observation mission in Syria even though he says Damascus has failed to adhere to an agreed peace plan.

The U.N. leader said Wednesday he wants 300 unarmed observers to be sent on a three-month mission, in a report to the U.N. Security Council that also said it was "critical" for President Bashar Assad to carry out his commitments.

The U.N. Security Council on Monday condemned "in the strongest terms" a coordinated insurgent assault on Kabul that marked the biggest militant attack on the city in a decade of war.

"The members of the Security Council underlined the need to bring perpetrators, organizers, financiers and sponsors of these reprehensible acts of terrorism to justice," the 15-member council said in a statement.

Syrian forces killed four civilians on Sunday in shelling of rebel areas and clashed with gunmen, testing a shaky U.N.-backed ceasefire as international monitors prepared to arrive in the unrest-hit country.

Forces loyal to President Bashar Assad subjected the Khaldiyeh and Bayada neighborhoods of the flashpoint central city of Homs to their fiercest bombardment since the truce came into force at dawn on Thursday, monitors said.

The U.N. Security Council on Saturday unanimously passed its first resolution on the Syria crisis, allowing an advance party of ceasefire monitors to go to the country on the brink of civil war.

U.N. Resolution 2042 approved the first 30 unarmed military monitors, who U.N. officials said could leave for Damascus within hours.

Russia on Saturday said the U.N. Security Council had "practically agreed" a resolution on sending an observer mission to Syria and called on all sides to strictly obey the Kofi Annan peace plan.

"The resolution on the deployment into Syria of a U.N. monitoring mission advance group has been practically agreed for adoption at the U.N. Security Council," the Foreign Ministry said.