Syrian troops bombed and shelled Homs today in the biggest bombardment of the rebel stronghold in months.
At the same time government troops made a push on Aleppo, the country's biggest city.
The higher pace of army and airforce operations suggests the Damascus government has been stung by claims that its troops are overstretched.
Homs has been one of the flashpoints of the 18-month-old uprising against President Bashar Assad's regime.
But the focus of fighting has shifted from Homs to other areas, including Aleppo, after troops got bogged down in April.
Today government troops were were mainly firing rockets and heavy mortars at the rebel-held neighbourhoods of Old Homs, Khaldiya, Qusour and Jouret el-Shayah.
They have also been shelling nearby villages and the rebel-held town of Rastan to the north.
And the army has bombarded Aleppo's Sakhour neighbourhood, with state TV saying it had been "cleansed of terrorists and mercenaries."
Meanwhile Turkey has deployed troops to the countries' common border a day after MPs approved military operations outside its border - including in Syria.
They didn't cross but troops and tanks gathered in Akcakale, where a mother and her children were killed by a Syrian mortar on Wednesday.
Syria said it was a mistake, but the members UN security council overcame their divisions to condemn it "in the strongest terms."
The council demanded an immediate end to such violations of international law and called on the Syrian government "to fully respect the sovereignty and territorial integrity of its neighbours."
Earlier in the day, Syrian ambassador Bashar Ja'afari delivered a letter to the security council expressing "deepest condolences" to the families of the victims "and to the friendly and brotherly people of Turkey."