Iran reportedly is preparing to send 4,000 Revolutionary Guard soldiers to Syria to defend President Bashar Assad's regime, as the United States intends to supply rebels with small arms through a CIA-run program.
Pro-Iranian sources deeply involved with Iran's security told The Independent that the decision to move soldiers into Syria was made before last week's presidential election.
Iran also is looking to open up a new front of the Syrian conflict in the Golan Heights region near Israel, The Independent reports.
Meanwhile, the U.S. is planning to bolster the strength of anti-Assad forces within Syria.
So far the White House has committed only to supplying rebels with small arms and ammunition, following confirmation that Assad's regime has been using chemical weapons.
On Sunday in Syria, Sunni extremists blew up a Shiite mosque in a village in the eastern part of the country that was stormed by rebels last week, another sign of the sectarian hatred growing in the country's civil war, activists said Sunday.
They said that the demolition was carried out by Al Qaeda's affiliate in Syria and shows the determination of extremists to drive Shiites out of the village of Hatla in the Deir el-Zour region near Iraq. Last Tuesday rebels battled pro-regime militiamen there, killing more than 60 Shiite fighters and civilians according to activists.
In amateur videos of the latest incident, fighters walked into the mosque in Hatla and trampled on books, some with covers showing pictures of Shiite clerics. It then showed an explosion that brought down the building, but its dome remained intact.
Sunday's video posted on the Internet appeared genuine and corresponded with other Associated Press reporting from the area.
Rami Abdurrahman, founder of the Britain-based Syrian Observatory for Human Rights, said that the mosque was demolished Friday, three days after the battle. Other videos that emerged earlier have showed rebels cursing Shiites and suggested fighters had burned Shiite homes.
"It's clear that they want to root out Hatla's Shiite inhabitants," he told The Associated Press.
The town was home to several thousand people, about 30 percent of them Shiites. It was considered a pro-regime community in the Euphrates River valley, where rebels -- including the Al Qaeda-linked group Jabhat el-Nusra -- have taken over much of the territory.
The Syrian uprising began more than two years ago with peaceful protests against President Bashar Assad, but later grew into a civil war that has killed nearly 93,000 people.
Most of the armed rebels in Syria are from the country's Sunni majority, while Assad has retained core support among the minorities, including his own Alawite sect, an offshoot of Shiite Islam, along with Christians and Shiites.
In the past year, sectarian bitterness has grown in the conflict. Each sect has been accused of massacres against the other, and Sunni and Shiite fighters from other countries have increasingly joined the battle.
Washington has expressed concern over last Tuesday's attack on Hatla.
Meanwhile, Assad's Jordanian neighbor and one-time Egyptian friend have grown frustrated with him.
Jordan's King Abdullah II told graduating military cadets Sunday that his key U.S. ally was ready to fend off any Syrian threats.
Abdullah said Jordan "will emerge victorious in the face of all challenges, the way we always have in the past."
Should the worsening Syrian crisis "become a threat to our country, we are capable at any time of taking the necessary measures to protect our country and people's interests," added Abdullah, whose country hosts more than 500,000 Syrians who fled the war.
Jordan, which backs the rebels against Assad's rule, is worried that the Syrian president may ultimately attack his neighbors with chemical weapons or that they may fall into the hands of militants if the regime collapses.
Jordan is hosting multinational military exercises involving thousands of U.S. troops. The U.S. also has agreed to install Patriot missiles along Jordan's 233-mile border with Syria and is allowing a squadron of 12 to 24 F-16 fighter jets to remain after the exercises.
Also Sunday, a Syrian official said Egypt's decision to cut off diplomatic ties with his country is "irresponsible," accusing Islamist President Mohammed Morsi of joining a U.S.-Israeli conspiracy to divide the region.
The official's statement broadcast on Syria's state TV came a day after Morsi told supporters in Cairo that his country is severing ties with Damascus, and closing its embassy in the Syrian capital. Morsi's decision was made amid growing calls from hard-line Sunni clerics in Egypt and the region to launch "holy war" against Assad's regime.
Morsi also called for a no-fly zone over Syria. The unnamed official said Morsi's call is a violation of Syria's sovereignty "and serves the goals of Israel and the United States" in the region.
The Associated Press contributed to this report.