(CNN) -- At least 31 people were killed during clashes in numerous Syrian cities Sunday, an opposition activist group said Monday.
The dead included 14 civilians and 17 members of the army and security forces, according to the Syrian Observatory for Human Rights. Tens of civilians and members of the military were wounded, the group said.
CNN is unable to independently confirm death tolls or events in Syria, which has restricted access to many parts of the country by international journalists. But the report came after another opposition group reported hearing heavy gunfire Sunday in Homs. State media didn't report any deaths or incidents of unrest.
Syrian security forces were involved in heavy shooting using machine guns and tank mortars, a second group, the Local Coordination Committees, said in a statement.
In the neighborhood of Bab Sbaa, explosions were heard and electricity was cut off on several streets, according to the group.
Also Sunday, employees of the Agriculture Department in Homs were attacked and injured by an "armed terrorist group," according to the official Syrian Arab News Agency.
The London-based Syrian Observatory for Human Rights said the deputy director of agriculture in Homs survived an assassination attempt when unknown gunmen fired shots at his car.
Another opposition group, the Revolutionary Council of Homs, said that the western Syrian city remains isolated, with all major roads cut off. The group also said landline telephones and the internet were not working in several Homs neighborhoods.
"It's like a war zone," a Homs resident and opposition member told CNN. This man is not being named by CNN for security reasons.
He said he could see at least eight tanks within a few hundred meters of his home, and that the constant gunfire he's heard since Friday increased in intensity Sunday during the early evening hours.
"I believe this nation wants the regime to fall," el-Arabi said. "And I know that we will pay a heavy price, but I want the international community to help reduce that price."
In a blistering statement issued Monday, European Union foreign ministers said Syria's President Bashar al-Assad "must step aside," adding the Syrian government's crackdown on anti-government protesters may amount to crimes against humanity.
"The EU is deeply disappointed that the UN Security Council has not yet been able to adopt a resolution on the current developments in Syria even after months of ongoing brutal abuses by President Assad and his regime," the statement said. "The EU will continue to press for strong UN action to increase international pressure and urges all members of the Security Council to assume their responsibilities in relation to the situation in Syria."
Last week, Russia and China vetoed a U.N. Security Council draft resolution condemning Syrian authorities for using violence against anti-government demonstrators.
Over the weekend, al-Assad and Foreign Minister Walid al-Moallem had harsh words for nations that appeared unsympathetic to their government.
"Syria will take strong measures against any country that recognizes the opposition council formed in Turkey," al-Moallem said, referring to a new alignment of Syrian opposition groups, the Syrian National Council, which announced last week in Istanbul that it will "represent the Syrian revolution."
"I am not interested in what they seek," he said, according to SANA.
"Do the armed terrorist groups want to hold a national dialogue? ... Do the armed groups, which assassinate intellectuals and scholars, want reforms in Syria?" he asked. "These groups kill people for money; therefore I don't see any relation between what they do and the reform program and the scheduled dialogue."
Al-Moallem was speaking to delegates from the eight-member Bolivarian Alliance for the Americas, who were in Damascus to show their support for al-Assad.
The al-Assad also met with delegates, stressing that the reform process in Syria will move forward "independent of any foreign dictates," SANA reported.
"The foreign attack on Syria got more fierce as soon as the internal situation started to get better, since what they want is not reforms, but to make Syria pay the price for its stances and defiance of the foreign plots in the region," al-Assad said.
Protests in Syria erupted seven months ago, and demonstrators want a Syria free of the al-Assad regime as well as democratic elections, they say. Al-Assad has been in power since 2000; his father, Hafez, ruled Syria for three decades until his death that year.
The United Nations estimates that more than 2,900 people have died since the uprising began in mid-March.
Opposition activists say the government crackdown is a systematic, sustained slaughter.
The government has consistently said it is going after armed groups.
Foreign Minister al-Moallem said Sunday that "the armed groups (have) killed 1,110 Syrians."
CNN's Yasmin Amer, Frederik Pleitgen and Hamdi Alkhshali contributed to this report.