ONCUPINAR, Turkey - Fierce fighting continued in Syria on Wednesday. Rebels sent reinforcements to the battered historic city of Aleppo as government forces stepped up attacks with helicopters and machine guns.
Activists say rebels set fire to a police station near Aleppo. They also say clashes and heavy shelling have continued in regions including Homs, Hama, Deir el-Zour and the Damascus suburbs as President Bashar al-Assad tries to maintain his grip on power.
The opposition Syrian Observatory for Human Rights says more than 40 people have been killed across Syria on Wednesday.
Watch related video of violence in Aleppo
Turkey Closes Border
Neighboring Turkey has closed key border crossings to commercial traffic from Syria but says they remain open for refugees.
Ankara says it is taking the measure due to security concerns. Last week, Turkish drivers said their trucks were looted and burned as rebels captured the Syrian side of the Cilvegozu crossing from government forces.
Analysts say the closures will affect Syria's economy by hitting cross-border trade.
At the Kilis refugee camp near Oncupinar, Syrian refugee Abu Hasan expressed support for Turkey's policy. "I think this is an appropriate decision," he said. "Turkey is making the decision to protect its border as well as to protect us."
The Killis camp houses more than 11,000 Syrians.
The number of refugees is increasing, with most using clandestine smuggling routes over the border.
Turkish Deputy Prime Minister Besir Atalay says more than 44,000 refugees are now sheltered in Turkey.
"There is an expectation that more people may come in," he said. "Therefore, today we have decided to build new camps in several locations including Osmaniye, Kahramanmaras and Nizip."
The Arab League has pledged $100 million to help the Syrian refugees.
Turkish Foreign Ministry spokesman Selcuk Unal says Turkey welcomes donations of equipment, but does not need personnel.
"Some of this assistance has arrived, in the sense of material assistance, and we are ready to receive more of the selected items that we have announced," he said. "And our open door policy will continue."
Reducing the U.N. Mission
Meanwhile, U.N. observers in Syria say their mission is dwindling.
Herve Ladsous, the head of U.N. peacekeeping operations, said the Syrian operation continues on a "reduced basis."
He told reporters in Damascus on Wednesday that the security situation in many parts of the country is "extremely delicate."
This image made from amateur video released by the Ugarit News shows a Free Syrian Army solider firing his weapon during clashes with Syrian government troops in Aleppo, Syria, July 24, 2012.
Free Syrian Army soldiers at the border town of Azaz, 32 kilometers north of Aleppo, Syria, July 24, 2012.
This image from amateur video released by the Ugarit News shows a Free Syrian Army solider driving a Syrian military tank in Aleppo, Syria, July 24, 2012.
This citizen journalism image provided by Shaam News Network purports to show a helicopter gunship flying a bombing run in al-Qalmoun, Syria, July 24, 2012.
This image provided by Shaam News Network shows smoke rising from Juret al-Shayah in Homs, Syria, July 23, 2012.
This citizen journalism image provided by Shaam News Network purports to show damage from heavy shelling of the al-Qadam district of Damascus, Syria, July 23, 2012.
A member of the Free Syrian Army points his weapon through a hole in a wall as he takes up a defense position in a house in Qusseer neighborhood in Homs, Syria, July 16, 2012.
A woman holds a child in front of their destroyed home in Tremseh, Syria about 15 kilometers northwest of Hama, July 14, 2012.
Free Syrian Army soldiers aim their weapons in Idlib, northern Syria, July 13, 2012.
This image made from amateur video from Hama Revolution 2011 purports to show a funeral for victims killed in Tremseh, Syria, July 13, 2012. (AP/ Hama Revolution 2011)
This image made from amateur video from Hama Revolution 2011purports to show families gathered around bodies of victims killed in Tremseh, Syria, July 13, 2012.
Members of the Free Syrian Army walk through Qusseer neighborhood in Homs, Syria, July 15, 2012.
On Friday, the U.N. Security Council approved a resolution renewing the observer mission for up to 30 days. The resolution allows for a pullout if the violence does not stop.
Earlier this week, the European Union decided to strengthen its arms embargo against the Syrian regime, blacklist nearly 30 government-associated people and companies, and ban the Syrian national airline from landing in EU countries.
On Wednesday, Russia's foreign ministry expressed opposition to the EU sanctions, saying they could be seen as a "blockade" of the country.
Some information for this report was provided by AP, AFP and Reuters.