The Syrian government has arrested family members of the Syrian Opposition Coalition delegation to the Geneva II peace talks, designating the delegates as terrorists and seized their assets, the US State Department said Wednesday.

In a statement, State Department Spokeswoman Jen Psaki calls on the Syrian government to "immediately and unconditionally" release all those arrested, including Mahmoud Sabra, brother of Geneva delegation member Mohammed Sabra.

"The opposition delegation must be permitted to safely and securely work towards the political transition for which the Security Council and the Geneva Communique have called," the spokeswoman said.

The second-round negotiations of the Geneva II international conference on Syria concluded in mid-February without tangible results, and the Syrian government and opposition even could not agree on a date for the next round of talks.

Analysts in Damascus say the Syrian opposition and its Western backers are exploiting humanitarian and military issues to pressure the government into concessions at the next round of their peace talks.

In the talks in mid-February, the opposition demanded the formation of a transitional governing body without any role for President Bashar al-Assad, while the government, gaining an upper hand on the battleground, insisted on prioritizing counter- terrorism discussions, saying al-Qaida-linked groups were mushrooming across Syria.

Esam Khalil, a Syrian lawmaker, told Xinhua: "the humanitarian situation in Syria has turned into a political asset for the West, " which supports the opposition. He also pointed out while the government was committed to aid delivery, some "terrorists" were hindering the process.