Obama looking for every available tool to stop Syria killings

US President Barack Obama has said that he is looking for "every available tool" to prevent the "slaughter" of civilians in Syria.

"We are going to continue to keep the pressure up, and are looking for every tool available to prevent the slaughter of innocents in Syria," Obama told reporters in joint media availability with the visiting Danish Prime Minister Helle Thorning-Schmidt.

The two leaders, among other things, discussed the current crisis in Syria, where, Obama stressed it is important that they not be bystanders during these extraordinary things.

"All of us who've been seeing the terrible pictures coming out of Syria and Homs recently recognize it is absolutely imperative for the international community to rally, and send a clear message to President (Bashar) Al-Assad that it is time for a transition, it is time for that regime to move on, and it is time to stop the killing of Syrian citizens by their own government," Obama asserted.

Referring to the international conference on Syria in Tunis, Tunisia, which was attended by foreign ministers of nearly 60 countries, Obama said that he is encouraged by international unity on that they are developing.

The Danish Prime Minister termed the situation in Syria as horrendous.

"I think it is also very, very true that we have worked together in that area. We must continue that endeavor, and just today we have seen that, of the leadership of the League of Arab States, there has been a step forward in trying to put pressure on Syria, which is very, very important," he said.

US Secretary of State Hillary Clinton, attending the first meeting of the "Friends of Syria" in Tunisia, warned that Assad would pay a "heavy cost" for ignoring the will of the international community after almost a year of brutal crackdowns on protesters.

She also announced $10 million aid for humanitarian efforts in Syria.