The first four days of the US visit of Benjamin Netanyahu have drawn much speculation of an open dispute between the Israeli prime ministerr and Barack Obama, the US president, over the borders of a future Palestinian state.

Today, Mr Netanyahu will have a chance to ease tensions with Mr Obama and possibly rally wider American support for his stance when he addresses the US Congress. He is expected to try to persuade its members that Israel should not be pressured to withdraw from the entire West Bank and should be allowed at least to keep major Jewish settlement blocs under any peace pact.

But Israeli commentators said Mr Netanyahu is likely to be careful not to widen a rift with Mr Obama to avoid further alienating the leader of Israel's staunchest ally.

The speech "will determine the rest of his term - a continued confrontation with the US that will push Netanyahu to his roots on the extreme right, or a bid to reach an understanding with the US president which would leave Mr Netanyahu in the centre and allow Israel an escape from its diplomatic isolation," wrote Aluf Benn, a political commentator, in the newspaper Haaretz. The tensions between the leaders began on Thursday, when Mr Obama said that Israel's borders before the 1967 Middle East war would serve as the starting point for negotiations over the boundaries of a future Palestinian state.

Mr Netanyahu had responded that the pre-war frontiers would leave Israel unable to defend itself.

Since then, Israeli and foreign media have been full of speculation about a souring of ties between Mr Netanyahu and Mr Obama, who has expressed frustration at his administration's failed efforts to reignite the peace process.

Haaretz said yesterday that there was "a lot of swearing" by American officials about their Israeli counterparts, adding that the US secretary of state, Hillary Clinton, viewed Mr Netanyahu with "something between hate and disgust".

The US television network ABC on Saturday quoted Aaron David Miller, a former US negotiator in the conflict, as saying that Mr Obama seemed to view Mr Netanyahu as a "politician-slash-conman". However, on Sunday, Mr Obama appeared to make an attempt to ease the anger of Mr Netanyahu and his right-wing coalition allies by stating in an address to the American Israel Public Affairs Committee (Aipac) that Israel would probably be able to negotiate keeping some Jewish settlements in the West Bank.

Haaretz reported that Mr Netanyahu's advisers viewed Mr Obama's speech at Aipac as stating a stance that was closer to the position of the Israeli government.

At home, the Israeli Right, the base for Mr Netanyahu's Likud party and its coalition partners, has rallied around the prime minister.

Avigdor Lieberman, the ultranationalist Israeli foreign minister, said yesterday that Mr Netanyahu's stances "reflect those of most of Israeli society". Moshe Yaalon, the vice-prime minister and a Likud member, was quoted in Haaretz saying "it's good that Netanyahu emphasised that the [1967] borders are indefensible… the prime minister knows the reality here well and has conducted himself with courage".

Tomorrow, right-wing politicians are expected to inaugurate a new Jewish neighbourhood in East Jerusalem in an event likely to draw international criticism of Israel's settlement growth and reflect the opposition of the current government to giving up East Jerusalem to the Palestinians.

The inauguration of the complex may cloud a European trip by Mr Obama this week, during which he is expected to reiterate his stances on how to renew suspended Middle East peace negotiations and draw the support of the European Union, where officials have increasingly condemned Israel's settlement enterprise.