The House of Representatives, following similar action by the Senate, is expected to unanimously approve a strong resolution supporting Israel in its conflict with Hezbollah and Hamas.
The seven-page resolution declares support for Israel's right to use appropriate action to defend itself against attacks.
Lawmakers say such defense includes conducting operations both in Israel and the territory of nations posing a threat to it, under Article 51 of the U.N. Charter.
The resolution notes Lebanon's failure to disarm and disband the Hezbollah under U.N. Security Council Resolution 1559 and it blames Iran and Syria for supporting terrorist activities against Israel.
There is strong bipartisan support for the measure, which comes against the background of intensifying Bush administration diplomatic efforts in the Middle East.
Congressman Steny Hoyer is the number-two Democratic leader in the House.
"The resolution simply says that we are not going to simply say Hezbollah is responsible for this," said Mr. Hoyer. "They are. The resolution says however that we understand as well that Iran and Syria are absolutely responsible for the actions of their agent."
Iran and Syria are sharply criticized in the House resolution, which demands that Damascus and Tehran end support for Hamas and Hezbollah and to direct those groups to immediately and unconditionally release Israeli soldiers being held captive.
In approving a similar resolution approved by voice vote on Tuesday, the Senate condemned Hezbollah, its state sponsors, Iran and Syria, and Hamas militants in Gaza.
Senate Democrat Joseph Biden urges the Bush administration to use its diplomatic clout to gather international support to pressure Syria and Iran to end support for Hezbollah and Hamas:
"For the world's own good, now is the time to put the screws on Syria, make the world united in their dissatisfaction and communicate it to the Iranians, build up the Lebanese capability, and focus on Hezbollah as the problem," said Mr. Biden.
Senator Biden said the statement by the G-8 group of industrialized nations was a good start by concerned nations to get at the root cause of the problem, namely Iranian and Syrian support for Hezbollah and Hamas.
The comments on Capitol Hill came as White House spokesman Tony Snow told reporters the administration is stepping up its diplomatic efforts, including steps to exert pressure on Iran and Syria.