The International Committee of the Red Cross says it is trying to broker a humanitarian cease-fire in Syria, as government tanks and troops mass around Homs and fears grow of a major renewed offensive in the city.

The ICRC's chief spokeswoman said Monday the Geneva-based agency has been in talks with Syrian authorities and opposition groups, but attempts to negotiate a cease-fire have begun only recently.

Carla Haddad said the ICRC is discussing several possibilities for delivering urgently needed humanitarian aid, including “a cessation of fighting” in the most affected areas. The group is the only international agency deploying aid workers in Syria and works in tandem with the Syrian Arab Red Crescent.

The announcement came as Syria's military sent tanks and other reinforcements towards Homs, sparking calls from an activist for women and children to flee the besieged central city. Homs-based activist Hadi Abdullah told the French news agency residents fear an imminent attack on Baba Amr, the main rebel stronghold in Homs. He demanded safe passage for women and children to leave the area.

Also Monday, two Iranian warships docked at the Syrian port of Tartous. The ships are reported to be providing training for Syrian naval forces.

Syria's president, Bashar al-Assad, still counts on support from Iran and allies such as Russia, which fears losing its main Arab partner. Earlier this month, Russia and China vetoed a Western- and Arab-backed U.N. Security Council draft resolution that endorsed an Arab League plan for Mr. Assad to cede power.

But the Syrian leader is facing escalating pressure and isolation from Western and Arab states.

On Sunday, two senior U.S. senators spoke out strongly in favor of supplying Syrian opposition forces with weapons and other aid. John McCain and Lindsey Graham urged international cooperation to help supply the rebels without direct U.S. involvement. Senator McCain said people “being massacred deserve to have the ability to defend themselves” while Senator Graham added that breaking Syria's ties with Iran “would make the world a better place.”

Human rights activists say more than 6,000 people have died in nearly a year of upheaval in Syria, where opposition activists have been rallying against President Assad.

A top U.S. military officer, General Martin Dempsey, said Sunday that foreign intervention in the Syrian unrest would be “very difficult” because the Assad government has what he called a “very sophisticated, integrated” air defense system and chemical and biological weapons.