U.N. leader Ban Ki-moon said Friday that increased attacks by government forces on Syrian cities "violate" the U.N. Security Council's demand for an end to hostilities.

The U.N. secretary general strongly condemned new violence and indicated he believes President Bashar Assad is using an April 10 deadline to pull troops and heavy weapons away from cities as "an excuse" to step up killing.

In the darkness, it was impossible for Umm Eddine to see her two eldest children as they trekked from Syria to Jordan. She wanted to call out, but knew any sound could attract army sniper fire.

When she set out into the cold night with her four offspring and several other families, the men smuggling them warned they must remain silent.

At least 23 people were killed as thousands of anti-regime protesters poured onto the streets across Syria on Friday despite a massive security forces presence and as troops pounded rebel towns, activists said.

Thirteen people were killed in the central province of Homs, six in Aleppo’s countryside in the north, two in the northwestern province of Idlib, one in the Damascus suburb of Douma and one in the Daraa Province town of al-Jiza in the south, the Local Coordination Committees, the main activist group spurring protests on the ground, reported.

Ankara has urged the U.N. to send officials to its border with Syria, where record numbers of refugees fleeing an assault by troops backed by helicopters have poured into Turkey in less than two days, a diplomatic source said Friday.

Foreign Minister Ahmet Davutoglu urgently called U.N. chief Ban Ki-moon in the early hours of Friday after more than 2,800 Syrians crossed into the country in the last 36 hours, reportedly fleeing a helicopter-backed assault by government troops, the source said on condition of anonymity.

Iran and Hizbullah have increased their military aid to the regime of embattled Syrian President Bashar Assad to assist him in his 13-month crackdown on protestors, Israeli daily Haaretz quoted Western intelligence reports as saying.

The newspaper reported that Israeli defense officials have said the potential fall of the Assad regime prompted Iran and Hizbullah to increase their involvement in the Syrian crisis.

A senior Hizbullah official discussed with a representative from the United Nations High Commissioner for Refugees (UNHCR) the conditions of the Syrian refugees in Lebanon, according to As Safir newspaper published on Friday.

The report said that the two officials held a meeting two weeks ago to discuss ways to aid the Syrian refugees in the country.

The United States on Thursday warned Syrian President Bashar al-Assad to respect a U.N.-backed April 10 deadline to end his "horrible" crackdown or face further international pressure.

Echoing assessments made at the United Nations, State Department spokesman Mark Toner said the United States saw no signs that Assad's forces were complying with the peace plan to pull out troops and guns from protest cities.

The U.N. Security Council on Thursday gave formal backing to an April 10 deadline that U.N.-Arab League envoy Kofi Annan agreed with the Syrian government to end its military offensive on protest cities, as a U.N. team dispatched by Annan to pave the way for eventual observers arrived in Damascus.

A statement, in which the council "calls upon the Syrian government to implement urgently and visibly its commitments" was adopted at a meeting on Thursday.

Syrian security authorities thwarted on Wednesday night the infiltration of an “armed terrorist group” from Lebanese territory into a town in Reef Homs in Syria, reported the Syrian news agency SANA on Thursday.

An informed source said that a member of the group was arrested after being wounded, while the rest of the members fled to Lebanon.

How does a country stay friends with both Washington and Tehran? How does it condemn the Syrian regime without alienating Iran?

These are the headaches troubling Turkish diplomats as Iran's nuclear program and the bloodshed in Syria put them in an increasingly awkward position with neighbors Iran and Syria and traditional ally the United States.