KUALA LUMPUR: Senior U.S. senators John McCain and Joe Lieberman said Thursday it was time to arm Syria's opposition as they expressed disgust over a massacre last week blamed on government forces.

"It's time to act. It's time to give the Syrian opposition the weapons in order to defend themselves. It's not a fair fight," the Republican McCain told reporters in the Malaysian capital Kuala Lumpur.

McCain is in Muslim-majority Malaysia along with Lieberman, an independent, for a brief visit that included a meeting with Prime Minister Najib Razak on Wednesday and other officials.

During their talks, the pair expressed their "repugnance and anger and disgust at the behavior of (Syrian President) Bashar Assad and the recent massacre of innocent women and children", McCain said.

Anger against Assad's regime has spiked over a massacre last week in which 108 people, mainly women and children, were killed in the central region of Houla.

Many Western governments ordered out senior Syrian diplomats in an apparently coordinated protest at the Houla killings, but Russia criticized the ejections as "counter-productive".

McCain attacked Russia and China for opposing aggressive action on Syria, and the U.S. administration of President Barack Obama -- who defeated the Republican in the 2008 election -- for not acting more forcefully on the issue.

"It is shameful that the United Nations Security Council should again be hindered by Russia and China by their vetoes for any significant action against Syria," he said.

"It is also embarrassing that the United States of America refuses to show leadership and come to the aid of the Syrian people."

Lieberman said: "In my opinion this will not get better until the rest of the world at least gives the arms to the Syrian freedom fighters with which they can defend themselves and their families."

More than 13,000 people, mostly civilians, are estimated by monitors to have been killed since an uprising erupted against Assad's regime in March 2011.

U.N.-Arab League envoy Kofi Annan left Damascus this week with no apparent concessions from the Syrian leader.