The two US senators made the remarks in a press conference in the Malaysian capital Kuala Lumpur on Thursday. McCain and Lieberman arrived in Malaysia for a brief visit and met with the Malaysian premier on May 30.
The pair also blamed the government of Syrian President Bashar al-Assad for the deadly clashes between Syrian forces and armed groups in the western town of Houla on May 25.
Head of the UN observer mission in Syria Major General Robert Mood said in a briefing via video from Damascus to an emergency meeting of the UN Security Council on May 27 that the UN observers in Houla estimated 108 people were killed, including 49 children and 34 women.
The UN Security Council condemned the violence in Houla during an emergency meeting on May 27, saying the clashes “involved a series of government artillery and tank shelling on a residential neighborhood.”
However, Syrian Ambassador to the UN Bashar Ja’afari censured the “tsunami of lies” by some members of the Security Council and said the Syrian forces were not to blame for the violence.
Also on May 27, Syrian Foreign Ministry spokesperson Jihad Makdissi said in a press conference in Damascus that the government holds “armed groups” responsible for the violence in Houla.
“We completely deny responsibility for this terrorist massacre against our people.”
Meanwhile, a number of Western countries announced on May 29 that they were expelling senior Syrian diplomats in an apparently coordinated move to protest the Houla killings.
However, the Russian Foreign Ministry said in a statement on Wednesday that the move was “counter-productive.”
The statement added that Moscow is “categorically against any outside interference in the Syrian conflict” because it would “only exacerbate the situation for both Syria and the region as a whole.”
Reports say Turkey has also decided to order out all Syrian diplomatic staff from Ankara.
The comments by McCain and Lieberman come on the same day when the so-called Free Syrian Army said the Damascus government had a “deadline by Friday midday (0900 GMT)” to end the turmoil.
Damascus has time and again blamed foreign-sponsored “saboteurs and terrorists” for the unrest that began in March 2011.