LIMA, Peru: US National Security Adviser Susan Rice condemned “heinous” bombings of hospitals in rebel-held eastern Aleppo Saturday, and top UN officials said they were “appalled” by the escalating violence.

Rice warned the Assad regime and its Russian backers they are responsible for immediate and long-term consequences.

“The United States condemns in the strongest terms these horrific attacks against medical infrastructure and humanitarian aid workers. There is no excuse for these heinous actions,” Rice said in a statement.

“The Syrian regime and its allies, Russia in particular, bears responsibly for the immediate and long term consequences these actions have caused in Syria and beyond.”

Rice indicated that the US government would use a summit of Asia-Pacific leaders in Peru to put pressure on Russia. President Vladimir Putin is attending the event.

“The United States again joins our partners, many of them gathering in Peru this weekend, in demanding the immediate cessation of these bombardments and calling on Russia to immediately deescalate violence and facilitate humanitarian aid and access for the Syrian people,” said Rice.


Extremely saddened

In a separate statement, UN officials urged immediate access to Aleppo, where government forces are waging a ferocious assault to retake rebel-held districts.

“The United Nations is extremely saddened and appalled by the recent escalation in fighting in several parts of Syria,” the UN’s humanitarian coordinator for Syria Ali Al-Za’atari and regional humanitarian coordinator Kevin Kennedy said.

They called on “all parties to cease indiscriminate attacks on civilians and civilian infrastructure.”

The comments came as government bombardment rocked rebel-held east Aleppo, where more than 250,000 people are living under regime siege.

The bombardment, which began on Tuesday, has killed nearly 100 people, according to a monitor, and forced hospitals and schools to close.

Za’atari, the most senior UN official based in Damascus, and Kennedy said the organization had a plan to provide east Aleppo with assistance.

“The UN has shared with all parties to the conflict in Aleppo and member states concerned a detailed humanitarian plan to provide urgently needed assistance to the inhabitants of east Aleppo, and conduct medical evacuations for the ill and injured,” they said.

“It is imperative all parties agree to the plan and allow us to secure immediate, safe and unimpeded access to provide relief to those most in need in east Aleppo, but equally in all other parts of Syria where there are people in need.”

The UN has not accessed east Aleppo since government forces surrounded the rebel-held side of the city in mid-July.

Moscow has organized several brief truces intended to encourage civilians and surrendering rebels to leave east Aleppo, but few have done so, and the UN has said it was unable to organize secure aid deliveries or evacuations within such short windows.

Russia is a key ally of the government in Damascus and has waged a military campaign to bolster President Bashar Assad’s government against rebels.

Moscow says it is not currently bombing Aleppo, though earlier this week it announced a “major operation” in neighboring Idlib province, as well as in central Homs province.

More than 300,000 people have been killed since Syria’s conflict began in March 2011, with anti-government protests.